Monitor goes off then right back on

[DukenukemX]

Been having strange problems with my Geforce 6800. Today I turned on my PC and both my Geforce 6800 and my Asus TV880 capture card could not start up. Under the general tab in device manager it would say device could not start. Messing around with drivers and stuff sometimes the Geforce would start up and sometimes only the TV880 would start up. Sometimes both started up and there weren't any problems.

After many driver reinstalls and stuff I decided to yank out my capture card and restart my PC 5 times to make sure my Geforce would work. It does work and it does start up except now I don't have a TV capture card. Unless my TV capture card was actually broke?

Now my Geforce seems to run fine except sometimes the monitors will flick off then turn right back on. It usually happens when I start watching a video or even when I start up my Hp solution center which is the software that I use to control my printer. Though when it happens it only happens once. Is this normal?

Also when I play World of Warcraft I would Alt+tab out to use FireFox or Ventrilo. Sometimes when I go back into the game it'll run slow as snot untill I shut the game off and start it back up. Is this normal to happen?