So I've had some ongoing mystery problems for a while. I'll try to sum up (I apologize for the length, but please bear with me): P4 2.4, ASUS P4S8X motherboard, Xp pro I've had a 512 stick of PC2100 RAM from crucial in my machine forever, and all seemed fine. I ordered a second 512 stick. After I stuck it in, started having some stability problems. Programs crashing, and even a few blue screens. I sent it back and got a replacement. Put it in, and again same problems. Miscellaneous errors in the event log, programs crashing. I woke up one morning to find my computer had totally bitten it over night. No recovering it. Fresh XP install. Learning from my mishap I also installed a second XP pro installation on my second hard drive. Even after my fresh install, I had some errors and had to run a repair on the installation. I then took the second 512 stick out of my machine again, and all seemed well again. I decided to use my second XP installation as my "test" install. So recently I put the second RAM stick back in, and have just been running my test installation. If it gets screwed I don't care. I ran memtest86 all night one night and it found no errors at all in the RAM. This got me to thinking about the MOBO. After my computer death, my floppy no longer worked. I tried a second floppy with the same results. It's not an OS issue because you can't even boot from the floppy. When in XP if you right click the A: drive it takes about 10-20 seconds for the menu to come up. Then if you click "format" it takes the same amount of time for that to come up. When you actually try to format it just whirs for a while then says "format could not be completed". Tonight, I had some errors every time I tried to install a security update. Since this seemed to fail every time, I thought I would take advantage of finally having something to work with that gave me a consistent result. To test my MOBO theory, I took out my FIRST 512 stick, the one that had never given me any problems, and left only the second one in. The update then installed fine. SO: Floppy is bad from boot up, and I apparently only have problem with BOTH RAM stick in. Either on on it's own seems fine (I am going to test this further throughout the next few weeks, using each RAM on it's own, and then with both together in different combinations of sockets). Opinions? Bad MOBO is the only thing I can think of, especially with the floppy issue. The RAM is a bit more ambiguous, but the fact that it only seems to have a problem with BOTH sticks in, and that memtest86 ran all it's test 7 times completely through and had no RAM errors also makes me suspicious.

Win9X (the forum you are on) has a problem with over 512mb of memory. Maybe XP has a similar problem.

Have you looked into your BIOS settings? Is the floppy detected in BIOS? Did you reload all of your mobo drivers? Make sure you RAM, and FSB are in sync. Make sure your PCI Bus is not overclocked. 33mhz. optimal, should not be greater than 40mhz. AGP slot should be 1/2 of your FSB. Check for ant RAM limitations in advanced settings. Try clearing your CMOS and loading optimized defaults. Post back with any updates that you have. Double check all of your connections. What is the wattage of your POWER SUPPLY? When you post back, list out the hardware you have installed. P.S. Xp does not have a size limitation on RAM like 98 does. It really not a limitation as much as it is a quirk. The only thing that would limit your RAM on XP is your mobo. Good Luck.

well if you had no problems before the new ram is installed and none when only one stick of ram is installed maybe it is just an incompatability between the two sticks of ram which is not uncommon when mixing differnent brand names of ram together