DO NOT USE IMAGESHACK.US OR INTERNET EXPLORER, UPDATE OR UNINSTALL ADOBE READER.
I never download any programs or say "Yes" to anything unless they're from a reputable site (e.g. Cnet's download.com). I haven't downloaded anything from the internet in the past three weeks.
I just got infected with a program called "Antivir Solution" by going on Imageshack.us (stupidly using IE). I didn't accept anything or click any dialogs, so was really angry.
The program got onto my system by an advert on Imageshack opening a .pdf file which executed the virus (which was luckily not too hard to remove once I got into safe-mode, but would otherwise not let me open ANYTHING or browse ANY webpage).
So this is a warning to you all: if you've been putting it off like me, make a backup of your computer now, stop using imageshack.us, stop using IE under any circumstances, and update Adobe Reader.
This is particularly horrible for me because I've reformatted several times in the past few months, and I am a very cautious computer user.