Malware is a likely scenerio here, however in order to be sure you will need to get your system running in order to perform scans and post your logs!
Try starting the computer with the "last Known Good Configuration" setting. To do this, follow these steps:
1. boot your system pressing the f8 key to access the menu options.
2. When the Windows Advanced Options menu appears, use the ARROW keys to select Last Known Good Configuration (your most recent settings that worked), and then press ENTER.
3. If you are running other operating systems on your computer, use the ARROW keys to select the Microsoft Windows version required, and then press ENTER.
This should allow to get back up and running to follow Keiths advice and also post your logs for assistance (if need be) in the Malware forum!
Good Luck :cool: