Try checking your virtual memory settings and disk space.
It can have some funny effects on different applications, particularly ones which make heavy use of memory like Flash and Photoshop.
Your pagefile setting in the virtual memory config should be at least twice the amount of installed memory in your PC (i.e.- if you have 64Mb memory installed, then set your pagefile to about 130 - 150 Mb) and make sure that you have at least double that in space on your hard drive.
This may not be the cure, but it has worked for me on more than one occasion when apps start playing silly games!