... I've never had to revert to a reinstall. Typically, I also find it unproductive, as you don't learn anything. Even if it's a bastard to track down the issue, you learn a lot from the experience, and that will help you solve the same or similar problems in the future. Reinstalling any operating system is a very blunt approach.
Whatever. I just did my umpteenth virus cleanup on a friend's computer. It took me 6 hours of fooling around with it (off and on) to get it cleaned up. As I didn't know the user's password, I had hacked the Administrator account, and used that one for the exercise. Turns out the virus had some stuff still stuck in the user's profile, and reinfected the machine when she started using it again.
So I'm done with trying to "clean" a PC with one of these newfangled super-virus/rootkit/remote-spam-server/fake-antivirus infections. The next time someone comes to me with a virus-infected PC, I'm going to get their data off, scan it with a couple of online virus checkers, wipe and reinstall their machine, and put their data back on. I could be done in a couple of hours.
Unfortunately, that's probably too much work as well, considering how few people keep their reinstall disks. If they haven't, it would be a reboot-fest of installing service packs, drivers, updates, and software. Bleh! Is this the best you can do, Microsoft? Really?!
Maybe next time, I'll just tell them to sell the PC on eBay and buy a Mac. (I'll even wipe the disk for them!) Will it solve everything? No, and spare me the usual rhetoric. The bottom line is that they'll be better off.