Desktop restarting by itself, overheat?

Greetings!

Firstly, my apologies for computer ignorance and my most sincere gratitude for your attention and patience.

My computer has been stable for around 2 years until last night it started freezing and restarting by itself, usually when there's a lot of applications running, or I'm running a game that requires a lot of memory and heats up my pc. For the record however, it has froze on BIOS setup too, which confuses me.

I figured that showing the system summary plus speedfan and additional info would help understanding so here:

i138.photobucket.com/albums/q279/TheDigitalKitty/spec.jpg
i138.photobucket.com/albums/q279/TheDigitalKitty/fan.jpg

Temp1 stays at 45-50ºC without any major application running and goes up to 60-65ºC when running World of Warcraft, I assume that's Mainboard temperature.

Because I'm afraid of overheat (Had past problems with a different computer because it was dusty - And yes, I'm keeping this one clean), I have an external mini-fan running and turned towards the tower to cool it a bit.

My computer is apparently virus and spyware free (Ran Avira and Spybot) and I have most my drivers updated according to DriverMax.

Let me know what additional information I can and should provide, I'd like to know if my PC is shutting down due to overheat and if not, what would you advice me to check?

Wow first off i hope PC Wizard is reading your DIMM voltage wrong, DDR2 should top out at 2.4 volts max for the fastest DDR2. I recommend taking out your RAM and looking for the voltage on it, and putting it in the BIOS manually. Then check if PC wizard shows the voltage that you input.

If PC Wizard shows the new voltage correctly you should download and burn memtest http://www.memtest.org/#downiso to see that there is no permanent damage to the DIMMS.

BTW: its not uncommon for a CPU of the NETBURST architecture to run up to 80ºC

try this- start>right click my computer>propertys>advanced>startup and recovery> uncheck restart on system failure

Hey and thank you greatly for the attention.

I've looked upon the RAM and it says "DDR2 512/667 Samsung", "DDRII 512M PC667" and "AK18V3208T-3 0640" Not sure about the latest, it was a bit hard to see. I can't tell what it means and what voltage it should be at..

What are the consequences of a DIMM with higher voltage than it should have? Could my RAM be damaged due to high voltage? I ran memtest last night and my PC restarted at roughly 20%, at which time the mainboard went up to 60ºC. What's the relation between high RAM voltage and high mainboard temperature (I heard mainboards should generally sit at 30-40ºC)?

Again, my apologies for my computer ignorance, I'd like to fix this with the forum help if it's a settings problem.

At this point I think you should try resetting the BIOS, if you can't find the jumper look here http://www.asus.com/product.aspx?P_ID=neVcvuSgEUZcO3rK navigate to the download section and grab your motherboard manual for the position. This will return your motherboard to its default settings. If your machine still reboots by itself it's most likely a power supply issue.

I noticed you posted on the Tech PC forums as well in which case the guy that replied to you is probability right about the RAM voltage being misread by PC Wizard.

As for checking the PSU, Unplug the power cord from the back hit the power button on the case to discharge it, remove it from the case open it up and look for capacitors that look like this (http://freepressblog.org/files/2008/10/img_3998.jpg) or this (http://borganism.com/misc/ga-7vrx_bad_capacitors.jpg).

Here's the symptoms of bad Cap http://en.wikipedia.org/wiki/Capacitor_plague#Symptoms

If any of the caps look blown it's time to replace it, and as always use the strip club rule when working in a power supply "Look but Do Not Touch"

Thanks for your continued support and patience!

The BIOS seem to coincide with what PC Wizard and Speedfan told me:
i138.photobucket.com/albums/q279/TheDigitalKitty/bios.jpg

I'll probably try to do as you say and reset the BIOS next, I was trying to avoid changing anything inside the tower as I really am not experienced in it. From what I saw earlier however, the capacitators look healthy to me, I took a photo of them as well:
i138.photobucket.com/albums/q279/TheDigitalKitty/tower.jpg

I also unchecked the 'restart on system failure' feature but without luck, after running memtest (not 86+) it rebooted by itself either way and froze on the first screen, when it shows my motherboard information.

I notice there is a wide discrepancy in the 12V readings in the two different reports. Either one of them is reading the system wrong or the power supply is unstable and failing. The BIOS report showing the 12V voltage is different yet again.