Windows 7 programs flicker when drop down menu is opened

This wasn't happening to me when I was on vista. It mostly happens in Lightwave 9.6 and Photoshop CS2. So the problem is that when I open a drop down menu in those programs the program either flickers a lot or it goes in the background and I have to alt+tab to get it back every time. It is really annoying because I can't do almost all important things in Lightwave and I can't save images in other formats in Photoshop beacuse of the drop down menu, and in other programs it flickers a lot and is just annoying.
Thanks in advance.