If you leave these things long enough the resident frequency of the instruction path will sometimes interfere with the CPU cyclical rate. I also understand the 1's get a little tilted over onto the 0's. It's called the Zero's and Juan's syndrome, after Uri Zero and Juan Spindleburg. Have you check for sunspots lately? I'd try the IEHGOD program. It's intended to fix anything. And if you buy all that crap, I've got an "antique" lamp with a genie in it I want you to buy ;-) "Honest, I didn't change anything in the program but the comments!" ;-)