Download and save the current version of Secunia PSI. You must save it, for this to work. Right-click on psi.exe and click properties, compatibility Windows 7 , click Run as administrator, apply and ok. Now install it and click no at the end. Now right-click on Secunia PSI in Start>All Programs, click on Properties, Compatibility, Windows 7, click Run as administrator, apply and ok. Now click on Secunia PSI and let it run. It works in compatibility as administrator for Windows 7, but not compatibility for Windows 8. Secunia, according to their blog will have an new version of Secunia PSI that work in Windows 8.1 out the gate sometime in December. Until then this method worked for me in Windows 7 Pro w/Media Center x64 (clean 7 Pro install,8 Pro w/M.c. x64 upgrade (saving nothing from 7) and all Windows updates for 8 and then 8.1 Pro w/M.C. x64 upgrade).