extremely weird problems

[kentuckyser]

Back in May I built a PC that has been running great up until about a month ago. Here is the parts list:

Asus A8N-E
ATI FireGL V5000
AMD 64 X2 4200+
Antec Sonata w/450w PSU
2 GB Corsair XMS PC3200 SDRAM
Sony Floppy
WD 250 GB HD
Lite-On DVD Burner
Lite-On DVD ROM

Ok, so the first problem started with getting errors while booting. System would POST fine, but would give me a checksum error, or another error while searching for PCI Devices. Sometimes I could get it to boot to Windows, sometimes it would hang. Each time it hung, it would restart itself and continue in that cycle. I called ASUS, they said it was probably a bad drive...floppy or dvd drive.

I removed all the drives and the PC started fine. I continued to use it ignoring the drive problem because we were busy at work, and didn't have the time to mess with it.

Then one day, it wouldn't start again. I still had all the drives disconnected. Contacted ASUS and they advised me to send the mobo in for repair as it probably had a bad BUS of some sort.

Got the mobo back from ASUS, they said the mobo was fine. No repairs done. I reconnected all the drives, etc and the computer booted to windows fine, but still gave me a checksum error....but it still booted to Windows. Well, it only booted fine once,....then the power wouldn't even turn on. The green light on the mobo was on, but if you press the power button, nothing happens.

So, again, I removed all the drives....now it boots fine...although still with a checksum error. So, I wanted to find out which drive was making it not boot. I plugged the floppy drive in, and gave it power. Hit the power switch,...and about 10 seconds into the boot I hear a weird buzzing sound...no display from the monitor. Shut it down, and tried again. This time, no buzzing sound, and still no display from the monitor. Ok, removed the floppy drive. Tried to start it up again but now it's giving me an error telling me a Windows/System32/Config/System file is missing or corrupt, and that I should repair Windows using the installation CD.

Can anyone tell me what the hell is going on with the system? Why would the PC not even power on when the floppy was connected? I guess I've narrowed the problem down to the motherboard, the PSU, or one of the floppy or DVD drives. Please oh please help me.

PS: When I built this PC, I built another one EXACTLY like this one at the same time and it's been running flawlessly.

[kentuckyser]

Ok, so I just started the PC and hit Delete to go into the BIOS. Got a blank screen with a little cursor at the top left,...but it never went into the BIOS. All the drives are still disconnected. The only things that are plugged in are the video card, CPU, RAM, and HD.

So, I shut it down via the switch on the PSU since the main power button wouldn't do anything. Unplugged the HD to see if that was the problem, now it won't even power on again. I hit the power button, nothing happens. The green light on the mobo is on, though.

Seriously, ***? Bad mobo or PSU?

[EzyStvy]

"Seriously, ***? Bad mobo or PSU?" -> you won't know till you start swapping out parts. I'd start with the PSU...

Have you had problems in the past with getting into the BIOS? If so does the machine have Variable speed fans that are plugged into the mobo? If so either replace the fans or plug them into a standard molex.

[kentuckyser]

I've never had problems getting into the BIOS. The only fans plugged into the mobo are the CPU fan, and the PSU fan. The case fan is plugged into a molex.

Thanks for your help.

[faint545]

As far as the "Checksum" error goes, try resetting your CMOS. Either use jumpers to reset it or take out the CMOS battery to reset it.

[mevensen]

I'd start with checking your memory, either swap some out (if you can); pull one module only, boot, try with the other, etc. (if you're running more than one); or run memtest.

Thereafter, start swapping other components (PSU, video, CPU, mobo) as possible, one at a time.

[kentuckyser]

Thanks for the help, but how would the video card, CPU, or RAM cause the PC to not even power on?

Wouldn't the fact that the PC will sometimes boot into Windows fine mean that the CPU, RAM, and video card are all ok? Besides, I always get a display so the video card should be fine.

[LeftyAce]

Ram can be flakey and the system can still boot sometimes. I just got an upgrade ram kit, and my comp worked fine for a while, until it started randomly hanging, so it is possible that your ram is the culprit. As far as not even powering on, though, I admit that doesn't seem to make much sense.

[newbuilder14]

No, bad memory can cause no video, freezing, restarting, and many more problems.

Try resetting your CMOS - checksum errors generally have to do with this - is your better seated firmly?

[kentuckyser]

I just removed the CMOS battery and cleared the RTC RAM via the jumper per the A8N-E manual. The PC is still non-responsive. The only indication that it's getting power is the green light on the motherboard is on,....yet nothing happens when I press the power button.

[faint545]

Last time i saw a problem like this (computer not turning on at all), which was when i was building my PC, the motherboard ended up being bad cuz i accidentally short circuited the board... maybe you short circuited your board? it is winter..

[glc]

Pull it apart.

http://forum.pcmech.com/showthread.php?t=132409