Unrequested Vista Shut Down Problem

So I'm working merrily along when my Vista Business machine closes my apps and shuts down without me asking for it. This happens almost hourly.

I've switched power settings to Custom where never shut down the display and never put the coumputer to sleep in case that was the problem. Also, I've updated my free for 1 year CA Anti-Virus and run scan and no virus found. Also also I've opened my case and checked my fans to make sure it isn't an overheating hardware type problem, FYI my machine is in stock state, ie no overclocking.

When I look in (right click) Computer > Manage > System Tools > Event Viewer > Windows Logs > System at the times it shut down, it says "Event 1074, USER32" and then lists some General and Detail info that I don't think is much help:

General =
The process C:\Windows\system32\winlogon.exe (DAD-PC) has initiated the power off of computer DAD-PC on behalf of user Dad-PC\Family for the following reason: No title for this reason could be found

Details =
- System
- Provider
[ Name] USER32
- EventID 1074
[ Qualifiers] 32768
Level 4
Task 0
Keywords 0x80000000000000
- TimeCreated
[ SystemTime] 2007-03-03T18:13:31.000Z
EventRecordID 3373
Channel System
Computer Dad-PC
- Security
[ UserID] S-1-5-21-91575-179281191-1487611339-1001
- EventData
C:\Windows\system32\winlogon.exe (DAD-PC)
DAD-PC
No title for this reason could be found
0x500ff
power off
Dad-PC\Family
FF000500
--------------------------------------------------------------------------------
Binary data:

In Words
0000: 000500FF

In Bytes
0000: FF 00 05 00 ÿ...

Any advice most welcome please ? ?

Hi Mr Alpha

Good point but I have/had two more tricks up my sleeve to try before resorting to that misery, first was that I had this PC hooked up to the keyboard + Video + mouse via a KVM switch so that I can use my work laptop (with Windows 2000) at home over the weekend with the same full size keyboard and monitor and second idea is to insert the Vista DVD and see if it will ask me to repair the OS, like XP does.

So I disconnected the Zonet KVM switch model KVM3202 and surprise but so far my new Vista Business PC has run 4 hours (while I grilled T-Bones for us and our guests, better than Salt Grass restaurant) without shutting down all by itself as normal! So fingers crossed but I've solved this problem

I'll leave the unit on overnight to double check and will revert.

Success, left PC on overnight with out the KVM switch and no unrequested Shut Down !

Looks like problem solved.

Just a thought.... All my friends have the same shut down issues... I finally fixed the problem... I loaded Linux Lint 6 ! I can use my PC using Linux without the hassles of unexpected shut-downs. Maybe that is a solution for you. Linux Mint 6 is free! It has OpenOffice suite and is compatible with all MS suite products.... My wireless printer works great with it as well! Setting up internet connections was a breeze.... Networking period was simple! Here is the link; http://www.linuxmint.com/

Maybe MS will get Windows 7 right... I sincerely doubt it how ever...