I have some files that I want to disable from start up in msconfig - I think they are associated with a Trojan virus. every time i untick the box to disable them from start up and press apply they retick themselves. None of the other files do it.

Any ideas?

Have you run a google search to determine what the files are? That is what you should do before going to try to stop them from working. They may need to be used to start your system. stopping them could cause your computer to not start and then you would not be able to do anything. Find out what they are first.

Download winpatrol (free) and use it to stop any start up programs/files as it is easier to restart them if need to! You can also stop services from within winpatrol

try the programm autoruns:AutoRuns for Windows

works fine!

Good luck