Try cleaning your star-tup programs. Do 'Ctrl+R', then type 'msconfig'. Go to start-up tab, and clear the unwanted items. Be careful you don't disable something important though!
Is anyone else tired of seeing this same question over and over again? People keep asking what's the best way to never ever get a virus. I always reply with the same thing:
Okay follow these steps:
1) Walk over to your modem.
2) Locate the power cable.
3) Grab the cable from the base, and pull...
It is most likely an optical problem, download a digital copy of the selected Windows OS you bought to a USB Flash Drive. Then just use the license inside of the booklet you bought when prompted to do so.