While the stacked magnets in the computers do eventually wear out, or get exposed to magnetic flux from other devices or even a thunder storm or static electricity, there are some other things I would check before I went to re-initialize your disk by F-Disk (PC Only). They would be:

Have you added or do you have a router.

Did you get a new cordless phone,

Satellite Dish Controller,

Break out tr he Fluke Meter and check the ground on your house,

But, most importantly of all, take your pen, stylist, and drivers, and try them on a friends computer, or a computer at a repair shop. If they work there, but not on your machine, then start looking for other things listed above, or consider re-initializing your HDD making sure to wipe the File Allocation Table(s) by removing the primary DOS Partition before you format the disk.

Yank My Doodle, It's a Dandy!