Intel PC Constantly Rebooting

A few more details please.
Which version of Windows?
What motherboard?
1 or 2 DIMMS, and type?
What wattage is the power supply? If 250 or less, that may be the problem.
What other hardware is in the system?

Some general suggestions to start you off with:

If this is an actual Intel MB, check for BIOS updates. Intel can be very prolific with BIOS revisions.
(I have a PIII board that wouldn't deal with 2 RDRAM DIMMs until I flashed the BIOS.)

Disable all on board periphials until the OS is running stable. Likewise, have just the Video card, and required drives connected.

Do not let Windows self load device drivers durring setup.
Load the proper drivers in this sequence:
Chipset / Motherboard drivers
DirectX
Video card
Monitor

Double check the clock settings for the CPU. While I havn't seen this on an Intel based system, some MBs for AMD CPUs set the clock speed wrong in Auto-detect mode.

Make sure that the video card is fully seated.
I have had 3 cases now where the supplied standoffs where up to 1/8" short.
The best way to verify, is to look at the interface between the card and the connector,
Remove the bracket from the card.
Reseat the card into the socket.
Check if the card seats further.Make sure that the DIMMs and CRIM are seated fully. The memory test in the POST will not detect memory errors that will stop Windows in it's tracks.

Chas

It sounds like your cpu is overheating. you might have changed the heat sink but you probably need a faster cpu fan. add auxillary fans, one to draw air into the box, and one to exhaust air outside.

This is an add-on to my first answer.
For some reason, the comment button didn't show up for me.

Chas

I have had so many problems with MBs not being able to read from the CD drive durring setup, that I now always copy the following onto the target hard drive:
The Windows install CD
WinZip
All device drivers
(I use a hot swap bay in my main system for this task.)

I had 1 system that kept locking up like you are seeing.
What I finally did to track down the problem was to perform a basic (driver-less) Windows install onto the drive in a different PC.
I was then able to find out what device was causing the problem. (turned out to be a bad USB controller on the MB)

Beyond the above;

Can you boot into safe mode?

Have youtried step by step with confirmation mode?
This might help find where it is locking up.

Hi,

I wonder if you simply have a dodgy power or reset switch?

Did you cange the whole case? Or just the power supply...?

Cheers,
Tim.

I have seen Graphics cards cause this problem, either due to a faulty fan on the board or the agp memory is no good. Another reason maybe that you are not loading the cchipset drivers for the motherboard which may also cause problems especially if yuo have a via chipset.

There is no current Windows version on the machine. Nothing has been loaded. Tried loading a couple of OS's. Win2K, Mill, Win98 and Red Hat Linux. Just as the GUI interface is about to start the machine reboots. Have changed the chassi and the power box. It is currently working off of a 250 watt power box but previously tried a couple of 300watt boxes. Exactly the same thing happened each time.

Exact configuration of machine as it currently stands.

20GB HD
256MB Ram (2 DIMMS)
32MB AGP Graphics
Shuttle PIII Motherboard (AV18E) (Most recent BIOS loaded)
52X CDROM
3.5" Floppy Drive
250Watt Power supply.

Some additional info.....I can boot using a floppy disk and can get to a DOS prompt but as soon as I try to run a setup or fdisk or format the HD the machine will reboot.

I agree with chas. It sounds like a very similar situation on my older PC. I have an MRT756 integrated PcChips mobo with a Pentium111 533B, 128mram, 52x cd-rom, Fujitsu 13.6gig, Win98se. While I enjoy crash after crash after crash, I had to do many a format and re-install of OS; and like you I could only get so far and all went to hell. I've spent unbelieveable coultless hours just trying to get the puter to work and finally someone taught me how to boot from a cd and put all necessary cab files on my hard drive so I don't have to put up with this anymore. Here are the instructions I was given for this. Bear in mind that I have all my info written down on recipe cue cards and I will write it the way I have it written down. (I need to do this because my cancer meds fog my brain..lol)
-To do a fresh Win98 install. As computer boots press "F8" to get to the boot menu.
-Choose "Command Prompt Only" and press "Enter"
-At the "C:\>" prompt type "format C:\(space)/q (space)/s" (don't use quotation marks when typing the command)(/q means quick format and /s means copying system files)
-Again at the prompt, type the letter of your cd-rom such as D: or E: and press Enter.
-Now at this new prompt, type: cd(space)Win98 and press Enter
-At new prompt(which should look like this, "D:\WIN98>") type: setup(space)/ie(space)/im(space)/is(space)/iv(space)/nr and press Enter.
-Now load mobo drivers>video card drivers>sound drivers etc...

Hope this helps.

Hi,

The other thing I was thinking was that if you were running the monitor off the PC's power supply and you have a dodgy monitor, then the power spike when its changes modes - like when you get to the GUI - could be causing your problems....Try running the monitor off its own power connection.

Cheers,
Tim.

With all that you have done, I think it's time to get ahold of a different motherboard and/or CPU.
At least for test purposes.

Another "test" would be to connect a scope to the 5 and 12 volt lines on a drive connector, and see if they dip significantly when the hard drive is accessed.
If the power supply drops low enough, the system will reboot.
Of course, you still need to determine which device is loading down the power supply.

If the drive connector voltages are solid, then check the output side of the on-board regulators.
This may halp you track it down to the MB, RAM, or CPU.

Chas

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