I have got same kind of problem here. Recently I brought a new LCD flast monitor to add to my excitement of working. But the monitor worked for 3-4 days with my preveous disply card. I have N-Vidia XFX 5600 display card with 128 mb ram on it.
Well, the problem started the very next day.When I want to boot up my pc, it just showed me the windows start screen and then went off, the monitor says no cable connection or check your display cable.But I have connected correctly.Now, when I boot up to safe mode, everything works fine.I uninstalled the display driver provided by my display card.Now my Pc boots up ok but without any display driver.
I am not sure whats going on here.But once I install hte driver, it goes off. I am on windows XP and UBUNTU linux.My linux boots up without any problem.
Please help. I think its the display driver confusing Windows.