PC start by itself

[ma]

I know there are a lot of Google postings regarding PC's
starting and shutting down on their own, but I have not
been able to find one that has a conclusive result.

Here is my "hair pulling" dilemma.
1- WinXP pro sp3 (or at least was sp3 when the problem started).
2- Dell E510, about 2 years old. Dell BIOS, Dell MOBO. Dell PSU (305 W
continuous)
3- Worked fine until about a week ago. Then as I was doing some
accounting on line, started closing open programs one at a time &
shut the unit down. Without any warning or error message of any kind.
Just as if I initiated the shutdown.
4- I restarted the unit, it worked for about 10-15 minutes, then started
the shutdown sequence.
5- I started most obvious troubleshooting sequence:
a) May be overheating. Opened the side, used a bigger/better fan &
constantly
checked heat sink temperature with an external thermometer & my finger tips.
Didn't
think it was running hot, thermometer showed around 110-115 F (so CPU could
be
no more than 125 to 130, and still OK).
b) Removed every item that I did not need. Sound card, ATI Radeon, all USB
devices except mouse & KB. Enabled onboard video. The same thing.
c) Disconnected from LAN & Internet, and then uninstalled virus scanner &
firewall.
No change.
d) Removed primary SATA drive, using XP CD made a partition on secondary
and installed a fresh copy of XP pro. The same thing. Start & shutdown
randomly.
e) Changed CMOS battery. Reset the BIOS to factory and adjusted there
after.
Checked all the screen saver, start on power restore, power on lan activity,
etc, etc.
f) Reseated all connections. No change.
g) Removed front power ribbon cable to eliminate possibility of bad switch.
Same thing.
h) Removed CD/DVD & burner & disconnected floppy. Same thing.
Like this AM around 5 AM, when the PC has been off for at least 5 hours &
cold
turned on by itself, and started making noise shutting down & starting up.
I had to yank
the power cable off and go to work.
6- I am at my wits. The only thing left is start spending hard earned cash &
first buy
a PSU. If that does not fix it, then I guess next is MOBO, and then
possibly CPU.
But my concern is that XP CD may not work because it is from an OEM company
with Dell MOBO or at least I may have licensing issues.

Sorry looks too long, but I am dying! Please if you know any step that I
forgot,
or you any suggestion that might help, let me know.

Mike

 

[Bob I]

Your subject says "PC start by itself", but your posting indicates a
shutdown. Since the "shutdown" is a "controlled" or "initiated"
shutdown, it is unlikely that you have hardware failure. Look in the
event viewer instead for what commanded the shutdown.

 

[ma]

You are correct. I hope I did not misstate my problem.
The problem started as "shutdown" in the middle of my work.
But now when I shut the unit down, after a random time span
the PC starts by itself. Then keeps shutting down & restarting continuously
until I pull the plug.
Nevertheless, I will follow your advise, and check the ev listing.
Mike

 

[Bob I]

As for the start up, you may find an entry in Scheduled Task, (if wake

 

[Allen]

Hello! I noticed you guys are going too much deeper. I have a question that I
don't know if you have checked. Did you checked at the switch on front panel
of your machine. I mean, see if the front cover might be pushing the switch
intermittently or continuously and this could trigger the cycle of ON and OFF
every 7 seconds.

 

[ma]

Actually I had done more than that.
I had removed the cable that connects front switch to MOBO. So no matter
how much the
switch is pressed, nothing happens. That didn't help. PC still doing it.