First check existing single 512MB chip. I inspected it physically, and checked what SANDRA said and, later, got the Crucial online scanner to tell me what it diagnosed. All agreed:
Existing chip: 512MB DDR 400 PC3200 non-ECC. (single-sided, 8 chips on 184-pin module brand: Elixir ??)
(Mobo: K8T-Neo-V 2 RAM slots)
Normally I'd buy a new Crucial chip, but I need this immediately and we may have a postal strike on our hands any day now, so I got a new chip from a local branch of PCWorld.
Spec of new chip (according to package):
512MB DDR 400 PC3200 non-ECC (single-sided, 8 chips on 184-pin module brand Integral). As far as I can tell, that's the same as the old one.
I opened the machine, put the new RAM chip into the second slot and started machine.
BSOD. Panicked (stupid, but I was tired) and failed to make a proper note of the error message - after years of shouting at others for not doing so!
Re-booted. Screen blank.
Re-booted, got it to respond to F8, and told it to go to Safe Mode. Got as far as a graphics driver and then stopped.
Repeat a couple of times, with similar results.
Took out new chip, leaving only old one in booted machine - AOK. Went online, checked out new scanner, demonstrated new settings for scanning in graphics prog. Tried different user, ditto. Really AOK.
Took out old chip, put in new chip, re-booted machine, it booted, I let it try to get into XP Normal Mode and then it gave me a BSOD with message:
"Windows could not start because the following file is missing or corrupt:
Well, it ain't missing (I thought it was not a proper filename to start off, but discovered that there is such a file sat there). As to whether it's corrupt or not I couldn't say, as check in Textpad showed lots of stuff, but it's obviously not a text file.
I've repeated this sequence several times now. With just the old RAM chip in, everything is just fine. With just the new RAM chip in, booting into Safe Mode stalls part way through; boot into Normal Mode and the file C:\WINDOWS\SYSTEM32\CONFIG\SYSTEM is - according to the machine - missing or corrupt.
The two RAM chips appear to have identical specs, so they should work together. Even if they didn't work together, then they should both work in the same way. Oh, and I checked the two chips plugging them into and out of the same slot, in case the second slot was a problem.
I'm sure that I got the new RAM chip thoroughly clicked in, and, presumably it can't be totally duff, otherwise I wouldn't be getting as far as not being happy with the "WINDOWS\SYSTEM32\CONFIG\SYSTEM" file. Or, alternatively, not being able to get more than part way through the list of files when asked to boot into Safe Mode.
I've not previously needed to update any configuration files (let alone BIOS settings) when just adding a second identical RAM chip - or at any rate not for too many years for me to remember.
Oh, and I didn't try the whole Repair your system bit. It takes ages and ages to recover all your settings etc from one of those, and, if I have to, I'll leave her with just the original - and apparently perfectly functional system but with just 512MB RAM. And if - my reasoning went - swapping the RAM would cure the problem, then "repairing" the system probably wouldn't.
I've prided myself on my troubleshooting skills for years, but this time (new emoticon to me, and I couldn't resist using it!)
I have to leave this PC usable by 4pm Saturday (UK time), and if I can't manage anything else I'll have to leave my mother to take back the chip and insist that it's their fault and get a refund. She's quite good at that sort of thing, but I want to KNOW what's happening. Ideally I'd like to know what's happening in time to get a full Gig of RAM working in her system. Suggestions anyone?
Edit: New AV prog (Avira) added in 3 days ago, now uptodate and showing clean system.
Edited by deeplyblue, 06 August 2009 - 06:30 PM.