Normans Malware Cleaner & Vista....

There are many other choices. Malware removal guide usually lists most recent programs that work best.

 

Just in case its one of those quirks with UAC and some applications that are not Vista compatible BUT may work if you run as Admin,

So uninstall, then install as admin, by right clicking the installer/setup file and choose Run as Admin, then once installed right click the shortcut icon and click Properties > Compatability > and tick Always Run as Administrator at botton > OK and try again.


Do you need resident or on demand scanner for malware in Vista?

If resident and to take over from the built in Defender then this is ok http://www.majorgeeks.com/Comodo_BOClean_Anti-Malware_d5616.html

If On demand then there are a few ok ones to run,
http://www.majorgeeks.com/SUPERAntiSpyware_d5116.html ( has a trial resident scan then reverts to on-demand after trail )
http://www.majorgeeks.com/AVG_Anti-Spyware_d5287.html ( again free after trial of resient )

http://www.majorgeeks.com/download.php?det=4281 (A-Squared, one I do like, good updates )