Go here for a very good FREE Online scanner and it will get rid of your Trojans etc, it's very good but it may take a while depending on how full your Hard Disk is. http://onecare.live.com/site/en-US/center/howsafe.htm?s_cid=mscom_msrt
As for a Registry Cleaner, go to www.filehippo.com and download Ccleaner and install it, also from the same sit you can get Superantispyware which is also very good and also Spyware Terminator, all of which i use regularly and FREE. Ccleaner is excellent for a good clean up of your PC and also the Registry and there is NOTHING to pay, especially that Online Scanner as well from Windows Live Onecare
Andy
February 2009