ok, so out of the blue my Dell Dimension 8400 gives me a nasty error at startup... something to the effect of "failed at checkpoint ITHR" and freezes on that screen.

I googled that error and found a bunch of potential causes and fixes. None of the easy ones (like replacing the battery or removing all USB devices) worked. On the more complex end, it seems that this error could be caused by bad RAM.

I bought the computer 4 years ago from Dell with 22 factory installed 512 sticks and just a few months ago threw in 2 more 1GB sticks purchased from eBay (and guaranteed to be compatible).

I pulled out the 2 1GB sticks and went back to the original setup. This time when booting, I got the Blue Screen of Death. I tried putting the 1GB sticks back in to reproduce the 1st error but now I cannot get anything but the BSOD.

It does not seem to matter how the sticks are arranged or which ones I have in. Each stick/slot is always recognized in BIOS and the error is always the same.

I called Dell tech support, who after taking me through the same excercises I did on my own, told me that either ALL of my RAM went bad at once or that it was a software problem and that I needed to reformat the hard drive. So my options are either reformat first and wipe out all of my applications that took about 5 hours to install and then if that doesn't resolve it buy and install new RAM or buy new RAM first and if that doesn't resolve it, proceed to reformat. I'm not really crazy about either option.

I find it hard to believe that each stick of RAM went bad all at once. Does that happen? especially if BIOS can see it....

Any other suggestions for troubleshooting before I break down and start reformatting?