You can download Trial Version of mcafee at http://download.mcafee.com/us/eval/evaluate2.asp
For Home Users and Individuals, AVG offers FREE Anti-Virus Software;
Visit : http://free.grisoft.com/doc/2/lng/us/tpl/v5 to download it.
Alternately, you can also do an online scanning using trend-micro online scanning tools;
You can Scan your computer from trojans using a online scanning tool. Click on the link below;
Anti - Spy Ware
If you have any spy ware installed in your system, you can remove them using this anti-spyware software.
Zone Alarm Firewall