New
#11
The hangs when both video cards are plugged in suggests a possible power supply problem? Could the two cards be drawing too much for the PSU you currently have? Just a guess on my part, I have no facts to back it up. What PSU do you have?
Can you remove
2. a 7 port "Plugable USB" hub
3. Creative speakers
and run that way for awhile, see if it makes any difference.
Do you use wireless mouse and/or keyboard? If so, try wired?