whyyy?! does it keep shutting down?! please help

okay, so here is the story. i got a new ATI fireproV5700 to replace my HD3870. and now my computer crashes when ever i play a game. my HD3870 never did that. i am running a 750 watt powersupply and looked into if it was a power issue. it's not according to neweggs calculator for power draw.

EVR Power Information
---------------
Current Setting: {5C67A112-A4C9-483F-B4A7-1D473BECAFDC} (Quality)
Quality Flags: 2576
Enabled:
Force throttling
Allow half deinterlace
Allow scaling
Decode Power Usage: 100
Balanced Flags: 1424
Enabled:
Force throttling
Allow batching
Force half deinterlace
Force scaling
Decode Power Usage: 50
PowerFlags: 1424
Enabled:
Force throttling
Allow batching
Force half deinterlace
Force scaling
Decode Power Usage: 0
Display Devices
---------------
Card name: ATI FirePro V5700 (FireGL)
Manufacturer: Advanced Micro Devices, Inc.
Chip type: ATI display adapter (0x949E)
DAC type: Internal DAC(400MHz)
Device Key: Enum\PCI\VEN_1002&DEV_949E&SUBSYS_00021002&REV_00
Display Memory: 2296 MB
Dedicated Memory: 504 MB
Shared Memory: 1791 MB
Current Mode: 1440 x 900 (32 bit) (60Hz)
Monitor Name: Generic PnP Monitor
Monitor Model: SyncMaster
Monitor Id: SAM0657
Native Mode: 1920 x 1080(p) (60.000Hz)
Output Type: DVI
Driver Name: aticfx64.dll,aticfx64.dll,aticfx32,aticfx32,atiumd64.dll,atidxx64.dll,atiumdag,atidxx32,atiumdva,atiumd6a.cap,atitmm64.dll
Driver File Version: 8.17.0010.1103 (English)
Driver Version: 8.911.3.4000
DDI Version: 10.1
Driver Model: WDDM 1.1
Driver Attributes: Final Retail
Driver Date/Size: 5/23/2012 23:31:16, 892416 bytes
WHQL Logo'd: Yes
WHQL Date Stamp:
Device Identifier: {D7B71EE2-D7DE-11CF-FD77-0820BEC2C535}
Vendor ID: 0x1002
Device ID: 0x949E
SubSys ID: 0x00021002
Revision ID: 0x0000
Driver Strong Name: oem7.inf:ATI.Mfg.NTamd64.6.1:ati2mtag_R7XGL:8.911.3.4000ci\ven_1002&dev_949e
Rank Of Driver: 00E62001

please help me!

 

If you overclock, I'd try turning those settings down, both in bios and in the video card, just to see if it stabilizes. I'd double check drivers too, just reinstall the latest vcard drivers available and see if that fixes it.

Start with a good cleaning, though. That always helps a computer