Hi Thunder -
Sorry I didn't get back here yesterday - wild day around here.
I just came down to my office and hit the power button and the 500 booted right up perfectly! This is really wild! Of course it told me "No Operating System Found" but I'm glad it did boot up ok. I'm wondering if all the hard shutdowns, the changing of the CMOS Battery and connecting that slave hard drive (to get the data off it) messed up the whole system somehow? I know I went into the BIOS and reset everything after I changed the CMOS Battery and I could have put a setting in there that wasn't there before - or not done something I should have. I didn't write down all the settings before doing that because I was having so much trouble getting into the slave HD and just wanted to get it going.
I've decided to return it to factory default and put 98SE on it because it came with a ton of discs when it was bought. Back the Gateway used to give all kinds of backup discs (even other vendors) and this being a high-end system it even came with games that were never installed. Even with my own 450XL, which also was a top-shelf system, I have a ton of discs that came with it.
I know support for 98SE has ended (or if it didn't it will very soon) and I read that support for 2000 is going to end this July. No problem as I never call Microsoft anyway. Plus I want to keep the retail W2K disc here.
I'm going to give it a few more starts and shut-downs and if all is ok the only thing I may do is up the power supply with an OEM pull I have from my 700XL desktop. This one (am on it now) needs a wicked format/reinstall of everything but will have to wait until I get the two older systems out of here one way or the other.
Thanks again for responding and I'll pop back in to let you know how I'm making out. As far as I know, there's now not a thing wrong with the 500 - which is really great!
Have a wonderful weekend!