dell 2007wfp flicker issue, PLEASE HELP

    I recently purchased a used dell 2007wfp lcd from ebay.  I've checked the amount of used time by holding the menu button while turning it off.  It has 1540 hours of use; ac power is 50 and soft key on is set to 55.  It seems to be in very good condition...I bought it from Tigerdirect ebay outlet store.

Anyways, anytime I turn on the monitor or it wakes up from sleep...it flickers for about 10seconds...especially noticable on the whites.  It then goes away and is not a problem.  I notice that if the monitor has been on for a while and just goes to sleep....I can awaken it with no problem, but if it has been off for a while....that is when I get the flickers as if the entire screen is shaking.   I have a atix300se video card with the newest catelyst 8.4 drivers. 

What do you guys think seems to be the problem?

Thanks,