Some assistance please

Hello,

my problem is this. suddenly a few days back my external router stopped working. when i got it fixed i thought my laptop would start working again, but it didnt. after running many different types of anti virue and spywear stoppers, it founf nothing, so i defragged and cleanup everything, and still nothing. so i did as it says on here and restored to factory settings. now this worked on the internet connection, it had set my windows back to the factory settings. and the net connection now works. the problem is now this. certain files wont install. Ultima online wont start up. and programs now take 5-10 minutes to start up. sometimes the windows explorer crashes or the symtech touch pad thing. also it randomly freezes and every so often the windows will wink on and off. again after search after search there appears to be no virus. i did not get a recovery disc or any type of disc with my laptop either. my laptop is a toshiba satellite. any help on how to fix this or whats wrong. ive tried factory restore twice.