The first thing I would try is safe mode. If the problem is not reproduced in safe mode, that will indicate this is a software problem, such as a driver incompatibility. Otherwise, you have a hardware problem, possibly with your video card.
I have a Dell XPS 730 - i7 - 965 @ 3.2 Ghz - 64 bit - GeForce 9800GT x2 - Overclocked X's 2 (factory)
Regarding "no signal detected" upon boot every morning this computer lose's it's signal to the monitor intermediately for about 20 minutes. During that time the signal to the monitor turns on and off some 3 to 6 times before it finally stays on for the remaining 16 hours of so before I shut it down for the night. It has not lost signal once it gets past its morning tantrums! Do you have any idea's? Thanks in advance, Dan