Alrighty then.
I clicked start, typed in “run” and then typed in “msconfig”.
I then went to the services tab and disabled EVERY microsoft program. The Sony “tech support” said not to do this but I decided it was the right thing to do. After enabling the programs in little chunks, I found that the two programs causing the problem were:
Windows Font Cache Service
Windows Presentation Foundation Font Cache 3.0.0.0
After disabling these two programs and then re-enabling everything else, Vegas resumed rendering.
I hope this helps anyone with similar problems.