if your computer has slowed down or you just want to make sure you dont have any trojans here a free scan from one of the best security systems on the net. it is a cleaning tool and if you have some to remove that it tell you to download the free trial, it will remove anything.http://ewido.net
Here's another free tool that in not old and they are not charging for it yet, and I use both Avorax below.
Avorax Shieldâ„¢ is a brand new type of personal security solution that is unlike to any firewall, anti-virus or spyware remover.
Rather than looking for spyware traces or tracking applications that secretly send or receive data over the Internet, Avorax Shield blocks any attempt by malicious software to add entries to the auto-start menu, change the registry, hijack or install itself into a browser or find any other way to stealthy get itself onto a PC.http://arovaxshield.com
And they also have a free anti-spywarehttp://arovaxantispyware.com