NIS 2011 Unable to complete Full System Scan

Hi, To make a long story short, NIS 2011 won’t finish any full system scans. It will go so far and then at some random file in my C drive, it’ll just hang. Task Manager will say the scan is still running, but it’ll be on whatever random file it decides to hang on for hours with no progress. Since I occasionally get little pop ups that say Idle Full System Scan is complete, I became suspicious and checked the log - turns out all Idle Full System Scans are cancelled, not completed. Quick scans will complete without a problem. If anybody knows what’s wrong or how to fix it, I’d greatly appreciate some help. I am running 32 bit Windows 7 Home Premium.