my pc crashes please do help

[maxtrixkhan]

i noticed a problem with my pc yesterday it
was running normally watching an hd video at at 1280* 800 resolution
the system became unresponsive and had to restart.
again it occured once again i tried playing an hd video
Used VlC media player both time
bought pc 2 months back

my configuration is
amd athlon X2 240 processor
motherboard - asus m2n68-am se2
3gb ddr2 ram 1 gb @ 800 mHz and 2gB @ 600mhz
hdd os in seagate 500 gb and secondary hitachi 250gb (i plugged in hitachi just 1 hour before this crash occured )
was online both the time
OS windows 7 ultimate
after that its now tunning smooth no problems yet
but not played an hd video since please reply
i am planning to buy an hd 5670 card soon will this be good or bad
used to play Hd videos regularly since i bought this computr, was no problem then . any problem with the motherboard ???????
please help

[vamsi_krishna]

Have you updated VLC recently. Sometimes, even my VLC player crashes when playing HD content. Try playing in different media players and see if the problem persists.

Say, K-Lite Mega codec pack. Download it, and play with it. Tell us what happened.

[Gollum]

Sometimes its just random. Sometimes the hard disk is the culprit. You said that you plugged it hitachi hdd were you playing the video from the same. If so then its your hdd. I can't make out the amount of ram on your system, is it 3gb or 4gb?