Strange Flicker

Hi there,
I'm new to the forums but after browsing here for a few minutes I can see that there are a lot of knowledgeable people here and I hope you can help me with my problem.
I recently bought a new sweet 22" monitor with native resolution of 1920x1080. The reviews were generally great and for the price of 180 dollars it sounded like a great deal. When I hooked it up to my laptop (via VGA) the picture seemed great at first but after a while I noticed some strange flickering (and not the kind you get with bad refresh rate). It is only noticeable on solid colors, grays and purple in particular. Its kinda difficult to explain but it looks like bright horizontal flashes running across the screen, about 1 cm wide. I know it sounds like I'm nitpicking but it's driving me nuts. Is there anything I can do about it?
I didn't have this problem when I hooked it up to my PS3 (via HDMI), but then again . . . its not always noticeable.
Additional info:
Monitor - ASUS VH222H (vertical refresh rate is 75 Hz but windows 7 isnt letting me go higher than 60 . . . hmm)
Laptop - Gateway M-series with Radeon HD 2600 (not the most powerful video card but its run Bioshock on medium settings)
Thanks in advance.
- Ivan