First, DON'T put magnets anywhere near your computer and disks.
Information is stored magnetically.
Putting a floppy diskette on a stereo speaker can erase it. Likewise, putting a refrigerator magnet on your computer case to hold up that latest Dilbert comic strip can hurt your hard drive. DO check for viruses at least once a week. All it takes is one infection to destroy all of your computer data. Next, if you're using Windows, DON'T just hit the power button once you're done using the computer.