Ran into an issue where in Windows 7 x64 the PresentationFontCache.exe process was taking an excessive amount of CPU resources and would not stop even after a clean boot. Here are the steps I took to resolve this:
[step 1] Click start and type services.msc into the search bar. Now find the Windows Presentation Foundation Font Cache 18.104.22.168 service.
[step 2] Stop the service and make sure it’s startup type is set to Manual.
[step 3] Navigate to C:\Windows\ServiceProfiles\LocalService\AppData\Local (or just cut and paste the path into any explorer window). NOTE – You may be prompted to allow this, just click OK. Locate and rename a file called FontCache22.214.171.124.dat to FontCache126.96.36.199.bak. Or simply move the file to your recycle bin (don’t delete it unless this procedure is successful in re-creating the file).
[step 4] Start the Windows Presentation Foundation Font Cache 188.8.131.52 Service, wait 15 seconds, then re-start the service. A new file called FontCache184.108.40.206.dat should be created automatically. If this happens, you can stop the service and safely delete the original file you had renamed to FontCache220.127.116.11.bak.