Hello! I am very frustrated with this issue! I had World Snooker Championship 2009 installed in my Windows 7 Ultimate 32bit and was working a charm! After a custom-clear install (format) with the VERY same Windows 7 Ultimate 32bit edition on the SAME PC due to virus problems now I am facing the problem that the title indicates! Firstly, I am the administrator of the computer and cannot switch to standard account as recommended from Widows 7...see attachments! Secondly I did the start-run-msiexec but does not work! When I type only "msiexec" a windows pops up...see attachments but just that! If I try to type "msiexec /unreg" nothing happens at all..! I read about that solution in other forum! Thirdly, I tried to install the game as administrator...nothing ...didn't work...the same message...see attachment! Moreover, I tried compatibility as XP SP3...didn't work either! What else shall I do! I know that I am missing something because I had the same game in the same OS in the same PC! Please help!!! Kindest regards! P.S. Have a look in the attached pictures for more info!