|"used to Be fine"|
Sounds like it is getting bogged down & a clean up is needed.
Start with TFC, reboot & try again.
Please double-click TFC.exe to run it. (Note: If you are running on Vista/Windows 7, right-click on the file and choose Run As Administrator).
It will close all programs when run, so make sure you have saved all your work before you begin.
Click the Start button to begin the process. Depending on how often you clean temp files, execution time should be anywhere from a few seconds to a minute or two. Let it run uninterrupted to completion.
Once it's finished it should reboot your machine. If it does not, please manually reboot the machine yourself to ensure a complete clean.