Thanks a lot, Blade.
My computer seems to be going fine now.
Opening new tabs in IE didn't need so much time (2 minutes at least when infected)
I'm using the free AVG antivirus and conducted a scan
Again it said that the GoogleToolbarNotifier.exe was infected with a trojan and a bagle.
(I had just uninstalled Google toolbar and reinstalled it the way you told me to)
I moved it to the virus vault and cleared the virus vault, and the google toolbar still works, but i think the files are somehow related, as it is the toolbar that takes a long time to run when opening a new tab in IE.
Anyway, thanks a lot for the help.