Oh god I have you all beat.
I went to a friend's house to fix his computer. He, his daughter, son, and wife all like to install freeware/shareware/trialware screensavers, gator, etc etc. It got to the point where his computer would crash on a 20 minute startup because it was trying to load so much stuff on boot. The first thing I did once I could do anything with the computer was to run spybot.
It had over 3100 things on it. It took spybot nearly an hour to detect and delete them all. I set it to run on the next boot and rebooted. It found another 80 or so programs to get.
So then I ran norton antivirus. He had about 20 viruses.
I then tried a disk defrag, and the windows defrag utility crapped out. It basically said: "dude, you're on your own" as the hard drive had something like 90% fragmentation. I had to download a 3rd party utility and let it run overnight to fix it. He said it was still running in the morning (~10 hrs after I had started it).
It was a P2 350 with 64 MB ram running win98 IIRC. He hadn't done any of the normal maintenance to it since he had bought it.