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
Power management: not disable usb ports
Check hard disk errors