Ok if someone else on earth did something as dumb as this and the solution is somewhere on this board just refer me to it, thanks.

I attempted to add a 20gig HDD from one "older" computer PentiumIII533 to a "newer" 1.7gig celeron.

My list of sins, and ommisions in the process sets me up to be voted stupidest guy ever.

I plugged them onto the same ribbon without resetting any jumpers, I didn't change the name (C:) for either drive, I didn't have a boot disk made up ahead of time, and when it didn't work no big suprise I just spent a LOT of time swapping hardware around pretty much randomly til I can't really remember now what was done when.

So...

What have I done from a hardware/CMOS/BIOS point of view?

If the two boxes with their original HDDs back in PLACE now won't even boot far enough to read from the floopy drive can I hope to recover either?

Is this actually the dumbest thing you've ever heard of anyone doing to two perfectly good machines?

If you put the 2 hard DRIVES back in thier pc's and u dont see them booting that means u probably did something in the cmos, because i dont think putting 2 harddrives on 1 computer can possisbly wreck the 2. Did u move the jumpers from master to slave on the hdd? if u did put them both back to Master , and when u wanna put them together in the same computer put 1 master 1 slave, the computer itself will name the drives for u. Im assuming u have 2 windows installations on both drives, which means that if u have both as master, then u can have problems.
Make sure u go to ur bios and load the default settings on each computer (it will tell u wat button to press to go into settings/bios). When the hard drives are on different PC's set them both as master, when u wanna put them on 1 computer, put 1 master, 1 slave. or 1 master, 1 cable select. They should both be recognized once u do that and everything should be fine. Remember press F8 to go into boot menu and choose which windows u wnana load up.

GLThanks for the reply.

I REALIZE I didn't put much detail in my original post. THe reason is my errors were many and varied and I figured it would make for easier demangling if I waited for folks to post possible fixes, most all of which I have actually already tried, with zero success.

SO, in fact I changed the jumpers, then changed them back when the drives went back into their respective towers.

Going to BIOS is the real problem at this point, I've tried to get at BIOS for both machines, but after counting RAM, and giving me an all clear post POST beep neither machine will not go past that point and I can't get them to F8 or anything. First of all we don't even know yet what version of Windows is on either machine...
2nd we know nothing about either machine...

Post alot more info and maybe we can find a solution to your current dilemna...The beginning would be to choose 1 computer and concentrate on it.

Leave the hard drive IDE cable and the power plug unattached and
see if you can get to the BIOS then.

Edit:Plus what patio said.