1. Disable Asus Surge Protection. Sounds like a nice feature but if it is getting in the way, get rid of it.
2. HDMI on the motherboard or the video card?
3. Not sure on this one, but the 4350 isn't the greatest, it is better than the onboard HD4200 though.
4. Hybrid Crossfirex won't work with that card and the onboard,
ATI CrossFireX? | GAME.AMD.COM
An ATI Hybrid CrossFireX™ system includes an ATI Radeon™ HD 2400 Series2, ATI Radeon™ HD 3400 Series or ATI Mobility Radeon™ HD 3400 Series graphics processor and a motherboard based on an AMD 780 integrated chipset, all operating in a Windows Vista® environment.
Ignore the 780G, his has the 785G and there isn't enough difference between the two IGP's to matter. The best you can get with using the two together is to enable the Surround View option in the bios and use both to run up to four monitors.
5. If it is the one I think it might be (more info would help), then it isn't the HDMI cable but something to do with IPv6, or at least that was the best I could find for that one showing up in my Event Viewer. My solution was to just disable the logging of that one item (Kernel-EventTracing).
How can i turn off the IGP so the computer only uses the GPU? would this be suggested?
If he isn't going to use the onboard, then yes it can be disabled; instructions are in the manual.