Finding the Problem System Shutdown.

Ok so 3 days ago Windows 7 suddenly shutdown my system for the 1st time, it rebooted after and event log showed "event ID 109" what ever that is.

It got worse over the day so much i couldnt use the PC anymore. it would just Switch power on and off like it was completly mad.

My temps look good i have Hwmon running allmost allways cpu like 30°C and cores 40-60° depending on load gpu 40° without load System depending on load 40-50° well i had some hot days before there it was going up to the 60° when playing games ad gpu 85° with load but that was on hot days and 85° is ok for a gtx460 i guess.

Since then i tried fixing it.

I changed my GPU for an old one without external power need same outcome it shutdown after like 30 minutes.

I changed to an older HDD.

Today i digged out an old PSU well the system ran for about an hour then it started again. windows tried emergency shutdown then power gone.

Reseated Rams aswell, only thing i havent touched is CPU i checked heatsink it looks okk and hwmon says cores 45° 41° 42° 39° so i guess thats not the cause either.

So is it motherboard or RAMs?

At the moment it runs it´s been up about 1 1/2 hour now. wonder if it starts bugging again.

Anybody got an idea what could be the cause?

http://social.technet.microsoft.com/Forums/zh/w7itprogeneral/thread/6cc741c1-f488-43ee-b762-bf5f8e814327

well this is what i found myself it´s something from powermanagment

so i 1st suspect was PSU but it happend with replaced PSU aswell i think it´s the mainboard or ACPI from it but i used this PC for 2 Years now and havent changed BIOS since.

i´ll try run memtest later see if that find something windows 7 own memtest didnt complain.

Well did memtest86 one pass no errors.

After about 4 hours uptime it happend again just shutdown.

Bump still havent fixed it, must be something with Hardware, can it be RAM should i try running it with just 1 Ram stick ?

It´s a i5 750 and 1333 ram.

Can cause bad ram such powerdown issues ?

Bump again still not able to use my main comp, have to use my old P4 i fixed with putting in replacement psu and some spare ram.

SO my main PC is a Acer Aspire M5810 i shopped about 2 1/2 years ago about 2 years ago i upgraded it with a GTX 460.

SInce then it worked flawlessly, well exept some reboots cause of high dpc cause of sound gone.

About 2 weeks ago this PC just shutdown, it tried to shutdown windows, must have been triggerd by ACPI. Then power gone, maybe a safty measure of the mainboard.

So far i tried replacement GFX i changed the gtx460 wich requires 2 6 pin PSU connections wich my PSU in this system actually has but on the same line. I exchanged to a 8600GT with passive cooling, it didn´t help. So i think the PSU is fine.

I removed PSU with a spare one from old PC wich i use right now, and it failed aswell since my old PC runs and it´s a 430W PSU and the one in the Acer is a 500W one i guess it´s powerfull enough.

Well i reseated RAM aswell once i put em in the worng slots i would just get a continus beep no boot when i put em back it worked for about 4 hours then again shutdown try from win7 then power off.

After a while the PC tried to reboot on itself but failed and just would shutdown over and over so i pulled the plug.

i then did load Bios defaults, after i changed 2 settings put harddisk back to ahci to make os boot and make quick boot without oem screen.

I just cant work out the cause of the power cut, it seems to be a safety measure to safe componets but i cant see High Temps or any failing hardware, i did memtest from a Linux CD well 1 Pass without error.

What should i do to pin down the cause of this shutdown problem. If i have to give this PC away to find the cause they wantt 39€ just for looking at it without replacement parts and i can hardly afford it.

Should it rip out the rams and run it with one at a time to see if it´s rams ? Or can anybody tell me it´s the OEM motherboard wich died.

Also if its the motherboard thats dead, how do i get Windows 7 to run after change cause it´s a OEM system is there a way when i let it be repaired and they replace Motherboard wich has not this OEM Slic to reactivate my System.

Realy need suggestions here what to do, i cant afford any expensive repairs or building a new system atm.

Like i said it´s a Aspire M5810.

Components in use.

Original CPU I5 750

Original Rams it´s Samsung something

Original HDD Hitachi deskstar 1TB

Original PSU 500W

Replaced GPU GTX 460

Original Motherboard FMP55 Foxxconn Acer OEM ****.

How can i find the error plz help.