BESR 8.5 can´t de- or reinstall/patch etc.....

Hi

Backup bExec System Recovery 8.5
Starting: Windows Instraller comes several times, but starting
Reinstall: doesnt work (Message, System cannot find Patchprogramm
Liveupdate: finds a patch,  doesnt Work (Message: wrong version
Stating again: Windows installer comes several times.......

How to remove the program to reinstall?