8800GT Sli Major Problems

HI, I purchased 2 BFG 8800gt512mb OC's 2 days ago to run in sli. I gave my computer a fresh install, installed the latest drivers , direct x 9 etc. I installed Crysis and after playing for a few minutes the sound goes and is replaced by a loud constant screeching noise. It has done it in other games aswell as Crysis (Battlefield 2, Juiced 2). I got a message saying turn down/off my hardware accelerator yet when I do this Nvidia control panel won't load up. This is my first sli setup, Here are my specs

CPU Intel Q6600 quad core @ 2.4 stock (Not GO stepping, think its B2 stepping)
Mobo Asus P5ne-sli s775 650i chipset
Ram 2gb Geil Ultra (have another 2gb of the same to install here after a mobo bios update)
PSU OCZ 600w
Graphics cards 2x BFG 8800gt512mb OC's
OS Xp Pro
HD's 2 x 320gb AAKS
Soundcard etc Creative-Xfi Extreme Gamer with 7.1 speaker system
Mouse & Keyboard Logitech G7 and G15
Display Teco 32" lcd HDTV @ 1368x765
Case & Cooling Antec 900 with 2 x 120mm fans in the front, 1 x 120mm fan at the back and 1 x 120mm fan in the side. Also the huge fan at the top of the case.

I plan on buying a new mobo next week (XFX MB-N780I-ISH9, nForce 780i SLI,) But don't really want to spend any more money on my rig until I can get sli working correctly.

Any help would be much appreciated as this is my first sli setup and I'm kinda lost :) Thank You

Here is the info I got from Windows Error Reporting:-

Follow these steps to solve the problem with a video device driver

You received this message because a device driver installed on your computer caused the Windows operating system to stop unexpectedly. This type of error is referred to as a "stop error." A stop error requires you to restart your computer.

Solution

There are two options you can use to try to fix the problem. If the first option doesn't work, then try the second.

Option 1: Install the most current device driver for your video card

* Go to the Microsoft Update website to see if there are any updated drivers for your video card. If there are any drivers listed, you should install them.
* If there are no updated drivers listed at Microsoft Update, and you know the manufacturer of the video card, contact the card manufacturer's product support service for assistance.
* If there are no updated drivers at Microsoft Update, you don't know the name of the manufacturer of the video card, and you need more help diagnosing and resolving this problem, contact your computer manufacturer's product support service.

Option 2: Manually decrease Hardware Acceleration for your video adapter

Technical Information
Error Message: STOP 0x000000EA THREAD_STUCK_IN_DEVICE_DRIVER (Q293078)