To be able to run all games that use PunkBuster on Windows 7, you need to hack it:
Go to C:\Users\\AppData\Local\PunkBuster\\PnkBstrB.exe and enable “Run As Administrator” in the “Compatibility” Tab
Go to “services.msc”, enable “Interact with Desktop” for PnkBstrA and PnkBstrB services
Go to C:\Windows\System32 (on x86 OS) or to C:\Windows\SysWOW64 (on x64 OS) and enable “Run As Administrator” in the “Compatibility” Tab
Same issue with the Release Candidate.
More info on the MVP Blog: Windows 7 PunkBuster fix
Please sign the Petition of Punkbuster for Windows 7