Random Lag video/audio either mobo or GPU

[Demo3017]

I have recently built my computer with my friends. It has begone to have random video/audio lag. I need help. Or should i try calling EVGA or Gigabyte.

Windows 7 Professional
EVGA SuperClocked 01G-P3-1567-KR GeForce GTX 560 Ti (Fermi) 1GB 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card
CORSAIR Vengeance 16GB (4 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600
GIGABYTE GA-Z68XP-UD3P LGA 1155 Intel Z68 HDMI SATA 6Gb/s USB 3.0 ATX Intel Motherboard
Intel Core i5-2500 Sandy Bridge 3.3GHz
OCZ Vertex 3 VTX3-25SAT3-60G 2.5" 60GB SATA III MLC Internal Solid State Drive (SSD)

i don't think it is the RAM but i may do another ramtest to check..

[Demo3017]

The video and audio just crashed. still not sure if it's the mobo or videocard

[Skullnit]

The video and audio just crashed. still not sure if it's the mobo or videocard

In that case you can just try to update the audio and the video driver and see if it is making any difference or not.

[Demo3017]

definitely did not work.
played COD2 at highest settings for 1 hour today and now about 5-6 hours after it is lagging again. although it hasn't crashed.
between every lag it changes my mouse pointer. is that an indication of which it is?