Viewports distorting

Sorry if the title is a bit misleading, i wouldnt know a other way to describe my problem. My problem is that if a menu overlay is in the active window anything displayed in the window is distorted and stuff isnt moving around correctly. As soon as im done interacting with anything in the window it clears the distortion and everything looks like it should again. Heres a example screenshot with and without the problem:


Im running this version (2.49b) of blender because im used to it, cant get used to later versions. Its the 64bit version, my os is windows 7 ultimate @ 64bit, my graphic card is a radeon hd 6670. It didnt always do that, before a recent formatting i didnt have this problem at all, i did make sure my drivers are up to date.
I hope someone knows a fix to this :/, thanks in advance for replies.