One idea: Try ... Photoshop>Preferences>Performance, and make sure your Scratch Disks are set to disks with a lot of free space.
Can you provide the full specs. of this computer - more info, the better. Pay special attention to the CPU, and the I/O, i.e. the HDD's, their speed, controller type, HDD speed, and how you have them allocated.
Also, please include the details of Windows Virtual Memory, including where the Page File is located, and how it's managed.
For some idea of the useful info, see this FAQ Entry: http://forums.adobe.com/thread/1042147?tstart=0
For issues on Ps speed, this FAQ Entry might be useful: http://forums.adobe.com/thread/1110439?tstart=0
Good luck, and please let us know more.
PS6 has been running just fine on this box for years now. There is plenty of HD space the drives used for swap files. It's just so strange. One day it worked fine and the next its unusable.
I would reset the preferences. If it is like all the rest start PS and immedialtly hold down ctrl/alt/shift keys. You should get a reset window.
Resetting the prefs did the trick. Thanks!