Not up on PD11 but my thoughts are :
Have you had a registry and temp file cleanup ? CCleaner
http://www.piriform.com/ccleaner
Are there hidden temp files that being generated but cannot be over written due to permission changed .
Can you render or re-render an old PD11 file ? or does it happen on only newer imported files ? (New equipment)
Has a Win7 update caused a problem ? Can you roll back the OS or driver updates. Some updates are automatic and you have no way of telling if a manufacturer has issued an update.
Unwanted services OR Antivirus running ? Stop all unwanted services especially those that have delayed starts or decide to scan the Hdrive after a time delay.
Probably everything you have already tried but may be a nugget of gold in the above
rgds
This message was edited 1 time. Last update was at Jan 12. 2013 11:43
Win 7 Home SP 1, PD 13
Processor i5-4460 CPU @ 3.20GHz, 3201 Mhz, 4 Core(s), (RAM) 8.00 GB, Sys Drive 120 gig SSD, Data Drive 1 Terrabyte, Nvidia GeForce GTX 750Ii , Portable USB3 2 Terrabyte