Thanks for your reply. I checked SpyCatcher & found that it hadn't detected any spyware & suspicious files so far. So I went & uninstalled it via Add & Remove Programs, despite the threat of spyware release.
SUPERAntiSpyware Professional gave a message today that it had expired. So I uninstalled it too.
The only antispyware I now have is AVG Anti-Spyware free version but it does not offer real time protection. I updated AVG Anti-Spyware & did a quick scan & it detected 14 tracking cookies, which I deleted.
Do you think I should download Microsoft's Windows Defender, which Tony Klein says offers real time protection?
Would you also recommend any changes to Mozilla Firefox, the browser that I always use?
Finally, how can I keep my registry clean?
Thanks for all your help.