Have windows 7 I am unable to uninstall "Advanced Registry Optimiser 2010" it comes up with "File c:\Program Files\Advanced Registry Optimiser\unins.dat does not exist. cannot uninstall" but it shows as 12MB?
It appears that you have ,malware,merely deleting the file may not cure the problem. Read above and follow instructions for Malwarebytes antimalware choose FREE version and download updates before scanning. I would not attempt a re-install at any cost.