A simpler and more user friendly version of Scarface212's registry editing techniques: Click 'Start', then 'run'. Within the run box, type the command 'msconfig' (again, without the quotes.) This will start an application specifically designed to configure what your system runs and what it dosent upon boot time. Far more user friendly than messing around with registry links, and its more less likely that you can accidently delete the wrong key or get lost or something. You are probably going to me most interested in the tab named 'startup'. Within here is a list of every windows application that is set to be executed upon boot time. If you do have a trogan, theres a 99.9 chance that you'll find it listed in here somewhere. Next question is "Which one is my trogan?" Its quite plausable that it could be discuised as some legitimate program. No easy way around this one, but if you know what should and should not be running on your system its not impossible. Applications such as "Taskbar display controls, Scanregistry, Taskmonitor, Systemtray, LoadPowerProfile, SchedulingAgent" are probably legitimate, so leave them in peace. Anything else left could be your trogan. Applications with names such as "Netbus, Backorfice, Sub7, Server" are suspicious, so they should be removed. If your not seeing any names such as those, you are going to have to compare a list of applications you know are installed on your system with those set to be executed upon boot time. Also, it might be a good idea to perform all these changes while in safe mode (Hit F8 before the initial Windows boot screen logo appears, then select Safe mode from the menu). The reason for this is you can be sure that your trogan is not going to be loaded with the rest of the operating system, so it dosen't have a chance to write itself back into the registry if it finds you have deleted it.

There, I hope thats helpful and not to lengthy.