Hi, I have pentium class machine with amd k5-pr 100 processor, san li sl-586v motherboard with 16mb 72pin ram installed, cirrus logic pci video card, 200W AT PSU, quantum HD, floppy and cd-rom drive. I use that computer as auxilliary machine at home. Few months ago I added a 32mb pc100 sdram chip, but it was recognised as 8mb chip. Last month i realised that motherboard does not supports ram of that kind, because it supports only edoram chips (two pairs of 72pin and 168pin 3.3v or 5v). At that time computer caused a problem. It didn't boot up. As I can remember there was no beep at startup and post messages, monitor stayed blank, hd spun up properly also cpu fan, but I can't remember how keyboard and tower leds behaved. I took the computer parts apart and put it back together again with no effect. I also turned it on and off few times. It seems I had luck just one time without sdram chip, I heard silent post beep and computer started normally with win 98se. When I turned it off previously described story repeated. I also tried reseting cmos, but still no success. Then I put back in slot sdram chip and I gave up messing around computer for two weeks. When I turned it on this time it worked normally again. I reconfigured bios and machine was giving no signals of any trouble, but ... One day at the begining of august I was writing a report, when time for lunch came. When returned, computer didn't respond at anything even reset switch didn't. I waited for an hour and nothing changed, so I turned it off, waited for moment and turned it back on. This time I noticed some strange things. Firstly hd didn't spin up, I immediatlly turned off computer and pull out power and ide connectors preventing possible further hd damage. I had had problems with that hd two years ago while it had erased itself and had been making clicking noise, but I recoved it and it 's working fine for half year now. During a year and a half I had booted from floppy drive as many times as possible, so I know how computer behave without hd. Lets go back to the story. When I started computer that time with cd-rom as primary slave and floppy drive, I heared strange sound coming out of cd-rom unit, I had never heared before. That seemed suspicious to me, so I took out hd to test it on my p4 computer and it worked fine with windows fully operating. Then I started research with non operating computer. I noticed some very strange symptoms. All keyboard leds are blinking randomly, sometimes once or three times in a row or even more. Power led is turned on as usually, ide led turns off, i say, after 30 seconds, turbo led stays off. PSU and CPU fan run normally. CD drive is making noise, when i turn on computer or when the tray gets closed. I also "removed" it, but still no effect. I also removed single component (ram, video, floppy, cpu,...), but I get no beep. Only without cpu floppy is making noise, as if it tries to read the disk. Normally speaker beeps if there is no cpu present, I tested that years ago. There is no video signal anytime. I start this thread, because I haven't traced similar problem before and I wish to have two computers in case of trouble with newer one.