Strange problem w/OEM rig...

OK< here's an odd puzzle. Almost a month ago, I installed a new stick of PC2700 in a family friend's machine. Passed Memtest, all was well or so I thought.

Last week ( why so long?), the computer (Compaq) decided it didn't like it The existing stick is Hynix I believe. Pulled the new stick, all was well, swapped in another known good stick I had lying around, no dice. All timings matched (2.5-3-3-7 I believe).

Comp presently has one 512 stick (the Hynix), she wants a gig. She has a second stick; what I didn't have time to try was taking the Hynix out completely.

So, to recap:
Factory Hynix stick: works fine
Anything in second slot: no dice

Here's the mobo information. I was hoping that a matched pair would solve this, but it does seem as if the RAM slot is the problem (I plan to check that the next time I can get to her house)...

BIOS update. 9 times out of ten that fixes the issue with OEM machines. Also try installing the new module alone in the slot where the Hynix is then install the Hynix in the second slot. It is possible that the memory slot went bad, however, I would suspect the underpowered Compaq powersupply.

BIOS update on this thing might be tricky as I don't think it has a floppy drive; is is possible to flash from USB (I have plenty of flashdrives) or CD?

Take an old Floppy drive round with a cable and plug one in with the side of the case off for a few mins.

We do it all the time on the new HPs/Compaqs at the office here that don't have Floppy Drives

I've never seen a Compaq without a floppy connector on the MB (you might need a molex to floppy power connector if there isn't one on the PSU lead set though, but there normally is)

I have had mobos with a bad DIMM slot. The alternate fix is to buy a 1 gig stick and use the good slot. You will not have dual channel but sounds like the speed won't be missed in this machine anyway even if it supports dual channel.

how old is this compaq? If it was made in the last 5 years it should be able to use a tool on their site to flash within windows, no need for floppy discs.

It's about 3 years old (give or take a few months).

She did purchase a second stick and recently found it, so next time I go up there (this weekend I believe) I'll pop it in and see what happens.

What I do to flash, is use a boot CD and just have either it load dos with a usb flash drive in a slot and just run it off that or burn it to the CD and just run it off that and flash it.

Compaqs are real finicky in how fast the RAM latency should be. They like low latency RAM. I had a similar issue a number of years ago with one of my Compaqs. Once I found out I was using 12ms latency RAM and I should of been using 8ms RAM, I got the issue corrected.

Compaq BIOS upgrades are done via ROMPaq. It will upgrade everything all at once. Nifty but a pain.

LOL I forgot that I helped my father in law upgrade his old P4. He kept looking for PC800 45ms RAMBUS and his machine needed PC800 40ms. He got lucky since he would of wasted money finding out why Compaqs are so darn picky on RAM. 45ms RAMBUS is very common, now the 40 is a little harder to find and more expensive.

While I know in theory the faster ram should downclock, Did her computer come with PC3200? We had the Hp version of that computer, Exact same Motherboard and it came with Pc3200. So I guess you might make sure both sticks are either 3200 or 2700.