Process Blocker is an ideal administration tool which can prevent running any application in Windows.
The tool (under development) is not a native process blocker so far  currently we have an automated process killer instead. It means that the running of an application is not blocked and a little time (less than one second) can pass until the tool kills a process. Thus one cannot prevent running some small utility requiring no user interaction and doing its job fast enough.
Compatibility: Windows 2000 and later (except Windows Me) (x86 and x64).
The current version of Process Blocker can be used and distributed free of charge.
Download: Process Blocker 0.7 Beta
