Dell 22" LCD blinking problem

[myogui]

hi all!

I bought an E228WFP (22") from Dell, right out of the box the screen blinks: image goes totally black for about 0.5 to 1 second and goes back on. The screen is brand new, this the second one I get, the the first screen I gotten a month does the same thing as this one. The screen is pluged via DVI.
The blinking happens only when I'm browsing, using Word, etc. It does not do it in games or when watching movies.

What I tried and did not change anything:
- plug on a different circuit in the house
- plug in the vga instead of dvi



see video: http://picasaweb.google.com/m.yogui/...88831590070050

Is it a screen problem or graphic card or electric? help!
thanks!