Forums mIRC Help In Windows Vista can't start mIRC

Hello users
I saw already some messages about problems with Windows Vista.

I'm using Vista some time ago and got the following troubles:
Impossible to start any version of mIRC.exe (i try with 6.21, 6.20)and it's not more possible to un-install them the official way. The installation i try in different folders and drives. The installation process working always fine. Everytime i want to start mIRC.exe (or when i will de-install) i get the following:
>>> Administrator rights missing, no access...

I'm the one and only user with full rights on my machine.

Any ideas?

Thanks for help!

Roland