Problem Watching and Capturing Video

Ive tried in numerous programs to capture footage with the same problem over and over again, as soon as i hit Capture Footage, my computer shuts itself off then reboots without any warning. Im using vegas video 6 and The same thing happens when i attempt to watch certain videos in Windows media player. This has happend to me before but i forget what i had to do to fix it, i believe it had somthign to do with going into the system file and changing some limits? not sure, any help would be appreciated.

 

Go to control panel admin tools and have a look in event viewer see if an error is reported at the time the computer shutsdown ,look in apps and system,go to control panel\system\advanced\ startup and recovery uncheck automatically restart,also go into media player and disable overlays also reduce video acceleration to 3\4

post the rest of your system specs you have given very little to work with,especially your video card and the driver installed

 

i have already checked for the automatically restart, im less concerned about the media player, sorry i didnt put specs, i didnt think i needed to because they werent needed last time this happend.
couldnt find anything special in the event veiwer, im not sure exactly what to be looking for and under which group.

Windows: Windows XP5.1 (Build 2600) Service Pack 1
Internet Explorer: 6.0.2800.1106
Memory (RAM): 504 MB
CPU Info: Intel(R) Pentium(R) 4 CPU 2.50GHz
CPU Speed: 2418.2 MHz
Sound card: Realtek AC97 Audio
Display Adapters: RADEON 9250 | RADEON 9250 - Secondary | NetMeeting driver | RDPDD Chained DD |
Screen Resolution: 1024 X 768
Network: Network Present
Network Adapters: Realtek RTL8139 Family PCI Fast Ethernet NIC - Packet Scheduler Miniport | Linksys LNE100TX Fast Ethernet Adapter(LNE100TX v4) - Packet Scheduler Miniport |
CD / DVD Drives: D: ASUS CRW-4824AH | E: Lite-On LTN486S 48x Max |
Default Printer:
COM Ports: COM1 |
LPT Ports: LPT1 |
Mouse: 3 Button Wheel Mouse Present
Hard Disks: C: 74.5GB | F: 0.0MB |
Hard Disks - Free: C: 53.8GB | F: 0.0MB |
USB Controllers: Detected: 4 host controllers.
Firewire (1394): Detected: 1 host controllers.
PCMCIA (Laptops): Not Installed
Manufacturer: Award Software, Inc.
Product Make: DM185A-ABA A335W
Serial Number: MXK3450J9J NA300
AC Power Status: OnLine
BIOS Info: AT/AT COMPATIBLE | 10/16/03 | ASUS - 42302e31 | |
Time Zone: Eastern Standard Time
Battery: No Battery
Motherboard: HP Pavilion 061
*** sorry about the exta stuff ***

 

look in system and application it will be the last event before your computer restarts,make a note of the time on your desktop clock then make it restart by trying to capture a video,leave the comp off for 5 mins then check event viewer for the last event at the time of the restart

notice you havnt got service pack 2 any reason?It really is an essential update for a smooth running computer and more importantly security