My computer has been running slow lately and I know it needs cleaned up. I have WindowsXP and weekly I run the disk cleanup, Spybot, Ad-Aware, McAfee Virus Scan and Spysweeper. When I run Spysweeper it always finds a Trojan Horse called trojan-agent.gen. I quarantine it and then need to restart to remove it. When my computer is booting up a window comes us that states the "remove failed". I then run Spysweeper again and the trojan horse is still there. How can I remove it permanently? Also I use Mozilla Firefox as my browser and it opens very slowly. It sometimes takes a minute or two to open once I click on it. Any help you can give would be greatly appreciated.