http://www.filehippo.com/download_ccleaner/
Then a disk defrag
I did both of those, but it still hangs at the desktop wallpaper.
could be corrupted system files or you just have something ugly running at startup.
Do a http://support.microsoft.com/kb/310353 and see if it still happens
I'll try that after my current scan with Ad-aware is finished
So you have nothing but a wallpaper?
I can't tell you how to fix it for good, but you can try opening task manager (ctrl+shift+esc) click file --> new task and then type "explorer.exe". That should bring everything up for the time being.
Other than that you might try booting in safe mode and see if it may be a bad driver or something.
How can you tell if its a bad driver? I havent updated my drivers or anything recently. The only thing updated was a Windows update a few days ago really.