|"I checked for dislodged items, and 1 512 ram card was loose. I fixed that. All others are fastened/ screwed"|
It's good that you found that. Problems with the connection of the ram to it's slot(s) can cause no video (blackness), and may or may not cause an error beep or an error beep pattern, but not an all White screen, in my experiences.
I'm assuming you have NOT fiddled with the ram otherwise after it last worked properly downstairs.
if you HAVE fiddled with it, make sure that the notch in the bottom of the ram modules lines up with the bump in the bottom of the slots. You can't easily get the latches at both ends of the ram slots against the modules if that's wrong, it won't go all the way down in the slot, and both the backwards ram module and the slot it is in are instantly damaged when you attempt to boot the computer - your mboard probably will not boot normally after that even if you remove the damaged ram module.The ram module will have at least one damaged or missing contact, and the ram slot will have hard to see black carbon deposits and the plastic and possibly at least one contact will be damaged. If you clean up the black carbon deposits and make sure no plastic or loose contact (it fell off of the ram module because of extreme heatiing) bridges contacts in the damaged slots by removing that, the mboard MAY work fine with undamaged ram in undamaged ram slots.
(How do I know ? I installed a ram module backwards once and only once, and I got someone else's computer to work again when they had done that - in the second case there was a loose contact in the ram slot as well.)
"Before activationg XP and installing updates to current SP. I had not even connected to the internet to do update XP, and still haven't."
"I had copies of the most updated drivers on disk for my sound and graphics. Perhaps I should have waited to install them. They were installed after XP was up and running (downstairs)."
"Thinking back, the install not only failed to detect the dotNet files on the XP install CD, but also stopped and claimed it could not read the cab files either. I thought I had solved that by copying them to another CD and inserting that, as the install detected them and continued."
The software on the hard drive cannot cause no video or abnormal video before the operating system loads.
Regarding your problems installing XP, see the beginning of response 3.
"2 beeps, 2 seconds apart. The BIOS bootup virus search/seek was turned on in last BIOS check. That is when it beeps twice."
So you're saying they're exactly the same as when the computer worked fine ?
"Tried the monitor with a laptop that had the correct socket fitting for cable. It worked fine there."
Good. Usually there's nothing wrong with the monitor, but it's a good idea to connect it to something else to make sure.
"Also yes to lights, fans, and drives blinking/ spinning."
Good. The power supply is at least partially working properly. However, other things can still be wrong.
"Well, I tried removing the 2 512 ram cards in case one had burned out."
Ram doesn't "burn out" or "go bad" unless something external to the ram damaged it, or you installed it backwards in the ram slot. or you pluggeed it in or unplugged it when the power supply had live AC power to it. 99% of the time when people think they may have a ram problem with ram that worked fine previously there's absolutely nothing wrong with it.
"This system requires pairing for the memory to work anyway."
No it doesn't, on modern mboards (made since about the mid 1990s). It may require identical ram modules to be installed in certain ram slots in order for them to run in dual channel mode, and all ram slots must have such ram modules in the right slots for all the ram to run in dual channel mode, but the ram will work in any ram slot even if that is wrong, but if it is wrong they all run in single channel mode. In the real world, there is very little actual performance increase from them all running in dual channel mode.
"I have since re-installed all 4 ram chips."
They're not chips, they're modules, or you could call them cards. All ram modules have at least two individual memory chips on them - most have 4, or 8, or 16 - 8 on each side. Some have 5, 9, or 18 (parity or error checking modules, which cost more) .
"I left the properly attached (2x) 1 gig memory cards in. I have since re-installed
all 4 ram chips."
You had two ram modules installed when the computer was working fine downstairs and you installed two more after it wasn't working properly upstairs ? That's NOT a good idea. You may have introduced further complications. If you know for sure which modules are the ones you had in it when the computer worked properly, install ONLY those modules.
All the ram installed must be 100% comptible with using it in the mboard model AND all of it must have the same ram voltage specified for it - some ram modules use non-standard voltages.
"Sorry for the slow response.."
That's okay - at least you posted again - it's much better you do that than you never post again like many people who start a topic here do.
"I have work related files (backed up) that I cannot access easily without my own computer"
If you mean on a hard drive on this problem computer, the hard drive can be removed and connected to another working computer.
"It's very hard to read the text on the power supply, but it appears to read 240v 12 amp max output "
Why is it hard to read ? Do you have vision problems, or are you just older like I am (I'm 60) and your eyes have problems focusing on small print. I use something such as a magnifying glass when I have problems with that, and better lighting helps a lot too.
Most power supplies can be used with either 120v or 240v AC. I don't think you've said where you're located. Some who post here are in the UK or Europe or Australia or New Zealand, etc. . In North America the standard household voltage is 120v, although 240v is standardly available for clothes dryers, electric stoves, electric water heaters, electrc welders in garages, etc. When the power supply or computer is bought, if the power supply can be set to either AC voltage, there is a recessed slide switch on the back of it that has already been set for the AC voltage of the country the power supply or computer was sold in or was intended for. Since it's recessed, it has to be deliberately slid all the way to the other side by someone to be set to the other voltage, so it doesn't get set wrong accidently. . If you take the computer to some other location, you may need to change the setting of that slide switch yourself to suit the AC voltage of where the computer is now located. If the setting of that switch is wrong, either the computer won't work or you'll fry everything in the computer.
It's really not all that important what it says on it, for the time being, unless it's max total (output) capacity is even less than 250 watts.
But, if you can, you SHOULD try connecting your PS to a working computer, or connecting a PS from a working computer to your mboard. The former will show you right away if your PS is defective; if the latter doesn't work, there's something else wrong with your computer.
Both take only a few minutes to try.
"I replaced the motherboard battery (the cr2032 "watch" battery) as well, as the original had not previously been changed."
A weak or dead mboard battery cannot cause the problems you're having. It can cause your operating system to not load if the bios Setup settings are, or your hard drive's connection is, non-standard when the bios loses it's custom settings, but it can't cause the mboard to not boot normally before the operating system is supposed to load.
The CR2032 battery has enough voltage for 5 years or longer after it was installed in most cases. It takes very little current to retain the bios settings.
If you had normal video, if the battery is too weak or dead, or installed backwards, or isn't getting a proper connection in it's socket, you would get a "Cmos Checksum Error" or similar message while booting, and when you went into the bios the time and date would be set to bios defaults.