itunes + windows = at best, slow, at worst, maybe what you have.
i'd try the kaspersky self-booting av disk (free) to see if you have malware - often that will kill enough of it to allow you to boot your o.s. to finish cleanup from your windows desktop.
at that point uninstall itunes & the residuals it leaves behind - will see if i can find my step-by-step itune residual remover.
just for sh 1ts and giggles, id run adwcleaner.exe and jrt.exe and tfc.exe - followed by a complete scan with malware bytes (mbam).
also, somewhere in there, boot into safe mode w command prompt and run chkdsk c: /f /r (yes, i know what you may post about using both flags...)
if that all fails,
boot into windows 7 (not safe mode) put the win 7 dvd in the player, and run setup from within windows -
theres a way to do a refresh that does not destroy your files or mess up your installed programs.
failing that... sigh... backup your stuff, drop the partition on c: and do a clean install.
edit - added "in" and "l" somewhere in the text for readability - bonus points if you figgur where...
