My keyboard "Delete" key is no longer deleting.

The "Delete" key on my keyboard is not working. I use the "Delete" frequently when typing, so this is making life difficult. I first noticed this early this am. I thought a reboot would probably clear it up. When I turned computer back on this afternoon, it is still not working. As far as I know at this time, all of my other system functions are working correctly. Not only that, but the functions of adjoining keys - PrtSC, NumLk, are all working. (Don't know how to test the "Insert" function - I'm not really sure of its function since if I place the "typing cursor" at a certain place and type, the characters insert normally without need of a special key). Stranger still, I went to System Restore. It always has about 2.5 weeks of restore points.  They are all gone.  The only ones there were:  7/12/2010 - System:Scheduled Checkpoint 7/13/2010 - 1:35:30 AM - Install:Windows Update This is doubly disturbing, as I have Windows Updates turned off ("Never Check for Updates - Not Recommended" setting). Just did a system restore to the 7/13 restore point (" Install:Windows Update"), but the "Delete" key still not functioning correctly - doesn't delete. ??? I'll do a scan now, but had scanned on 12th or at latest 11th with no problems. I guess I could restore to the 7/12 "Scheduled Checkpoint", my only other restore option - should've done this instead of using the 7/13 checkpoint - but I'm always a little fearful of doing more than one restore, as I've had a crash in the past from doing that.