Precaution is even better <<

Keep an eye on suspicious activities

If you happen to see any special feature in your computer then be careful it might be a Virus Attack. E.g. computer starts functioning slow, the light of floppy drive starts blinking even when it is not in use, size of the file differs, stray messages on the screen etc.

If any such things happen without any changes done by you then it could be a virus infection. For which it is always better to scan your computer.