Underpowered computer in terms of memory is not likely the problem. That would simply slow everything down.
One possibility is a problematic video driver. Try seeing if there are any updates for the video driver for the video card (or chip) for the system.
That's true, but that type of arrangement is still controlled by a video driver which might be the wonky link here.
And by the way, the idea of reinstalling the software to try fixing this type of problem is ridiculous!
I will check the updates for video card next monday. And i recall one point that i am using 21" monitor with 125% display setting, that may be the cause. But i have to check it next monday because it occurs on the computer in my office.
BTW, i don't think the cumputer is underpowered, it is Dell 755 with new installed Win 7. It works easy and smooth.
Thanks for all your replies.
Set the view back to 100%. Also try turning off Aero.
There have been many reported problems with that combination reported
with earlier versions and I don't have Win 7 installed anywhere to check.