Stuck on blue"loading personal settings"

Hi,
i have a problem with Win Xp. My pc is clogged up with adware and other junk. I went and installed an adware remover and antivirus package, when it said restart your pc to allow settings to be complete i did. when the user log in screen came up i clicked my account and it just froze and will not budge, i have left if for over an hour and still nothing. Can someone please help? How do i bypass this screen to fix the computer and save my important documents? any help is greatly appreciated.
Regards

David