Computer reboots after starting game

[RealCosmo]

I just downloaded and installed halflife2 from steam. Then i launched it and wanted to start a new game in the main menu. i get a black screen with a white loading progress bar and when the loading is done, my computer reboots automatically. i've checked already all settings in the options and they seem to be alright. any idea, what can cause this problem???

 

[FireGiver]

what are your system specs? Because I had a similar problem when I would be playing a game my machine would reboot. I upgraded my powersupply and no probs now.

 

[RealCosmo]

my system: 1,4 ghz amd, 512mb ddr, gefore4 ti 4200, 350 watt ps.
i played already doom3 without any problems.

 

[FireGiver]

do you know your mother board chipset??? if its via there might be an issue. http://www.viaarena.com/Default.aspx?PageID=5&ArticleID=9

 

[RealCosmo]

yes i have a via chipset. i just downloaded the newest graphiccard and motherboard driver. Let's see if they can fix the problem. if not, let's see what else can be done referring to the article you posted. thanx!

 

[FireGiver]

Sigh its as I feared another via victim. Ive bought nothing but via for 3 mobos now and the fourth is going to be nvidia.

 

[RealCosmo]

ok, the two new drivers didn't worked. i just completed download of half-life source and by launching that the same problem appears. ANYONE OUT THERE who has ANY ELSE IDEAS??