This is the configuration of my rig... AMD Athlon 64 3200+ MSI K8N Platinum Motherboard Transcend 2*512mb XFX Geforce 6600 graphics card... Western Digital 80 GB SATA HDD i also have a server grade power supply so i know it isnt a power problem... I have Windows XP Professional Installed... Service Pack 2 pre-installed. i have DirectX 9.0c installed... Now the thing is that i used Xp home edition temporarily and everything worked fine there..Here the problem is back. everything else works fine...but when i play video,after a few seconds the monitor switches off and the sound plays on a loop..i have no other choice but to restart...this is very annoying..strangely, i can play games like moto gp2 without any problems...but when i try games like tachyon or freespace 2, it hangs immediately. Same goes for any video i play in any software. My monitor is working at a refresh rate of 60Hz which the nvidia software itself selected. Please help me out with this..this is getting on my nerves... Thanks in advance.