Avast Antivirus asked me to delete a probable virus and to restart to perform a checking.

I had to stop the checking at the middle of the procedure as I needed the computer. It was imposible to turn off the computer pushing the power button (as it entered in suspension mode, no matter how long I kept pushed the power button). I removed the battery as the only way to restart the computer.

Windows 7 said that there is a problem to iniziate Windows. Windows 7 tried to fix the problem without success. Windows 7 started after that though.

Everything is OK but the USB mouse. The USB mouse sticks and freezes each couple of seconds more or less. The tactile mouse (PS2) works well.

I googled for solutions but the posible solutions didn't work for me.

What happened? How could I fix it without formatting and reinstalling everything?

UPDATE: this is what I did:

• Change the mouse from one usb port to another

• Test another mouse

• Set the number of cores of the CPU manually with msconfig

• Power management: not disable usb ports

• Check hard disk errors