Hi ellen,
like the toshiba guys, I suggest you a reinstall, too. After a while an operating system becomes slower and slower due to misconfigured setting (does not matter which settings), and the
registry becomes more and more full and causes the system to make really weird things.
So, it would be good to backup you important data and reinstall windows with the recovery cd. After that you should have a clean and sober (from 3rd party software) system.
Would appreciate some feedback if you perform that reinstall.
Greets