Cannot program chips using ISP3 or AVRISP Mk II

I have a very frustrating problem: I am suddenly unable to program any AVR chips. I have been using the E-Lab ISP3-USB and Atmel AVRISP MkII for years, now neither of them will program properly. I have tried using various computers, running WinXP and Win7, and various of my project boards that use Tiny26, Mega8 and Mega48 chips. I even tried using a laptop with a newly-installed WinXP, that didn't have any other programs or USB drivers on it. The result it always the same.

The AVRISP cannot enter programming mode and gives an error message that says to check the programming frequency and check the CKDIV fuse. Even when I set programming freq to 125KHz or less, it does not work. I can't program the fuses either.

The ISP3 says "wrong device ID: 00000, Mega48 (or whatever chip I'm trying to program) expected", then "Target false ID xxxxx".

I am out of ideas. Has anyone seen this problem before?

maybe your programming Cable from programmer to processor is broken??

i also receive this message when i plug the cable in the wrong direction onto the device to be programmed.

I have two E-Lab ISP3 programmers, one original and one upgraded to Xmega. Also two AVRISP's. They were all acting the same way.

I did have success: I got out a new, unused Mega48 and wired it up with minimal connections to an ISP header. I was able to program it! So perhaps the other chips had the RSTDSBL fuse set or had some other problem. I'm still baffled by why this occurred with three different chips.

Thanks much for the suggestions.