I had almost the identical problem a couple days ago, but all it seemed to be was that I had some sort of memory problem....I cleared caches, re-booted and it went away.

Now, there ARE Windows "temp" files and such that get very large and, I think, become part of the memory problem...ordinarily, anything in C:\windows\temp can be deleted, thus clearing space, if nothing else.

Still, as Max so eloquently said, re-booting generally clears these situations.

Do you have any helper application...like Norton Utilities?...and do you de-frag semi-regularly?