More than two years after I wrote this first blog entry dealing with the subject, having come up against this problem time and time again without being able to fix it, I went and did some experimenting on a PC at work to see if I could find a solution.

Short version: Instead of trying to swap the drive letters around by renaming the \DosDevices\ registry keys, I’ve discovered that if you delete the lot of them, Windows will recreate them when it next boots (as many of them as you have discrete disk drives plugged in at the time), and on the machine I tried it at work today it worked flawlessly: it reassigned the boot drive as C:\, the CD drive as D:\, the four card reader slots as E:\ through H:\ and everything was fixed.

Longer, more helpful version: If you’ve just added a hard drive to your PC (typical scenario: it’s the ex boot drive of an older PC you’ve just decomissioned, and you want the data off your old XP install) and Windows no longer boots, getting stuck instead just before the welcome screen with just the windows XP logo showing and no “Please wait” text below it, it’s very likely that XP’s suddenly developed an identity crisis of sorts and is referring to the new drive as C:\. It’s stupid, really quite illogical, and basically poleaxes that install unless you’re willing to play chicken with the registry.

Fortunately, this game of chicken is reasonably tried and true, and it’s easy enough to figure out if you’ve got even a bit of technical familiarity with your PC (as you probably are if you’ve just opened it and plugged another hard drive into it).

Hit Windows + R to bring up the Run dialog (probably you can also get to it by clicking your Start menu and then “Run…”), type regedit and hit enter. This will load the Registry Editor, which is basically a precision scope that lets you look inside your operating system’s brain. This particular registry key – HKEY_LOCAL_MACHINE / SYSTEM / MountedDevices – lists the mapping between various disk drives on your computer and their respective drive letters as visible in My Computer.

What happens is that it sometimes gets confused about how to refer to your boot volume, and if your boot volume’s drive letter changes after you install XP, it will probably get stuck partway through starting up and hang just before the Welcome/login screen.

The information here might also be of interest/use to you if that drive letter was D:\ or E:\ or something else other than C:\ from the moment you installed XP, and you want to change it back to C:\ without having to reinstall again.

The fix: Deleting each of the \DosDevices\ values shown in the registry in the above screenshot will cause Windows to recreate and reassign the drive letters in your computer. If XP’s not booting anymore, obviously you can’t just run regedit like above, but there are ways around it. There do exist commandline tools you could run from a floppy disk or something, but by far the easiest way is to grab a registry-editing liveCD of some sort. I use Mini XP on Hiren’s BootCD, but this tool should do the trick easily enough for most.

This procedure has so far worked to bring Windows XP back to life on both a customer’s PC at my work, and on my own laptop at home (on which I dualboot XP and 7 for just this sort of messing about). If you try this method, leave a comment or email me and let me know how it went!

Update 10/2: If you have programs installed to drive letters other than C:\, be aware this could wreak havoc with those. Windows may be intelligent enough to reassign the driver letters with respect to installed programs, or it may not be. I haven’t tested this, and being a rare set of circumstances I doubt I’ll ever have the opportunity to. Your best bet in that situation would be trying the old manual renaming method. Remember you could delete the DosDevices entries to fix things enough to make it bootable again, and then swap drive letters D+ to your heart’s content to get your other programs to work without reinstalling those.

A customer at work wanted me to take Trend Micro Internet Security off his PC. The only problem was someone’d helpfully password-protected Trend, and nothing could be done without the magic word. After some fruitless googling, I gave up and called Trend Micro Australia for help.

I’d long considered this a last resort for any problem, but was pleasantly surprised with the outcome. The guy I spoke to asked for my name and the serial number of my product. I said I didn’t have the serial number, but went on and explained my problem to him.

Far from refusing to help me without that little bit of information (I’ve been hung up on by tech support from other companies for not precisely following their rulebook), the fellow immediately latched onto the problem and told me to Start -> Run -> tissuprt, which is a kind of maintenance program for Trend products. It provided a very simple GUI with a button to uninstall all Trend products from the PC without requiring the password. Exactly what I (and probably you googlers) needed.

I mentioned to him the trouble I’d had in finding out how to do this, and he said it’s actually on their website, plain as day for anybody to read. He helpfully emailed me the link, and here it is.

Full marks to the company for the phone support, but the reason I couldn’t find that page in the first place is because nowhere on it does it have the word “password”. Go look, I’m not kidding. Nobody who’s needed this information has been able to find it, because inevitably their search is phrased around not having that password.

Anyway. Hope tissuprt helps somebody.

Haven’t had a chance to update much lately – work’s been flat out, I’ve just had all four wisdom teeth out (with almost no pain, fortunately), and every other second of my spare time has been spent racking up hours on my Ls (nearly done!).

My laptop service manual page has nearly quadrupled the number of visits to my site – I’m getting close to 15,000 page views every month now, and that number is steadily increasing. To celebrate I thought I’d share a few oddities I’ve found while searching for various manuals.

This is the service manual for Radio Shack’s TRS-80 Model 100 computer. This was way before my time, and I don’t think I’ve actually seen one in the flesh.

This (click for full size) was the full list of screws used to hold one of these together. While modern, intelligently designed laptops are built with maybe four or five different sizes maximum, back in the day Apple liked to make things as hard as possible (I suppose they still do) with this mix of nine Torx screws. I’m glad I never had to disassemble a 550c.

These images are from the service manual to the original Mac Mini. Where some companies recommend a flat-head screwdriver, and Apple themselves have previously included handles, the official tool for separating the two halves of a Mini is a sharpened putty knife. They include instructions to make your own, or you can order the official part – number 922-6761.

1. Melt a 4 litre tub of vanilla icecream in a large saucepan.

2. Dice two large Mars Bars, Cherry Ripes, Crunchies and Turkish Delight bars. You can chop them as finely as you like, but it’s best when they’re nice and chunky.

3. Heap the chocolate bits into the saucepan with the icecream and stir until consistent.

4. Carefully pour the whole mixture into a large bowl lined with Gladwrap (to make getting it out easier later on) and smooth flat on top. Put the bowl in the freezer and let it sit. Upend onto a very large plate, and serve in slices. Voila – icecream pudding, an awesome Christmas treat for climates where Christmas day often approaches 40 degrees celcius.

This isn’t really relevant to anything else on my blog, but in the interests of freeing information I thought I’d share this for Google to find later.

I was trying to find the exact dimensions of the boot space in an early model Smart ForTwo coupe – the 0.7L engine model made between 1998 and 2006 (I think it’s the 450, the new one built starting in 2008 is the 451), but could only find it quoted as “170 litres”.

I couldn’t find the actual numbers anywhere on the internet. One helpful forum thread suggested about five inches cubed, likely from someone who’s only seen pictures of the thing and immediately dismissed it as rubbish. I wound up emailing someone at the Mercedes Benz dealer in Sydney, who replied (on a Saturday!) with the information I was after.

So: The boot space in an old ForTwo is 95cm wide, 70cm tall and 50cm deep. So nearly a metre wide, and a bit taller than it is deep.

Just for fun, I have compared that to a 32″ widescreen TV on sizeasy.

This computer suggested an insane screen resolution:

This MSI laptop recommended one:

This file doesn’t exist, but it might if you delete it:

This is what a touchpad looks like, under the cheap paint:

This is the cleverest virus I’ve ever seen:

(If you have this “Windows XP Professional”-branded virus on your computer – forcing you to solve a CAPTCHA puzzle every few minutes, lest it reboot your computer – hit ctrl+alt+delete and close rundll32.exe. Then download and run combofix and then avira to get rid of it.)

“Okay,” he said, “try it.”

So I tried it. I pushed the clutch pedal to the floor, started his car, pushed the gearstick left and upwards, and let out the clutch to see what’d happen.

And of course, the engine went into first gear with no power behind it whatsoever, and immediately stalled. A little orange light appeared among the instruments, asking me very politely not to do that again.

“Cool,” I remarked, grinning like an idiot with a new toy. Then settled down and mentally prepared myself for the first proper test run.

Clutch in, turn the key, clutch out and accelerate. The engine raced with the merest suggestion of movement from my right foot, causing me to panic, over-correct and pretty much completely lift off the pedal. The car stalled again, bucking sickeningly to and fro this time, before settling gently back into the dip in the ground of the empty car park we’d found for this experiment.

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Thinking of buying a USB hard drive?

Obviously you’re gonna go for the one with the longest warranty – three years will surely see you through your CompSci degree, yeah?

Hold on for a minute. There’s a point I’d like to make.

Hard drives are reasonably equal beings, nowadays; some tend to fail more than others, but it’s impossible to tell for years after they’ve hit the market, and nobody’s going to wait that long. They’re also a very competitive market, where prices fluctuate by mere dollars and cents every week, and when the pressure gets as high as it is now, they’re going to cut costs everywhere they can to stay in the game.

They can’t cut many corners with the drives themselves. I’m talking about the cheap crappy boxes they put them in.

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On the side of a machine that rents trailers at a servo:

Airport Krispy Kreme:

Guess the restaurant:

What a dead pixel (and a very small portion of the fileserver at work) looks like: