Backup your data onto a backup media like CD-RW, DVD, USB drive, external hard disk, or other media.
Turn off external drives only after shutting down main computer to avoid file corruption.
Install anti-virus software and keep it up to date.
Do not move computer while it is powered up, mechanical damage may occur.
If you hear any unusual noises, (such as clicking sounds from the hard disk) shut down computer immediately to prevent data loss.