Press ctrl+alt+delete and look at the different processes running. If you see one that does not look familliar, go to
http://www.answersthatwork.com/Taskl...s/tasklist.htm and check to see what that process is. If it's something bad, click it and end process.
There's a few complicated ways to stop a program from starting up. What I've found to be the simplest way is to go to
http://www.neowin.net/cgi-bin/files/...?file=startcpl and install that program (download will start automatically). The program adds an entry to the control panel and it can be used to control what programs start up with the computer. It's very easy to use (no need to check multiple startup locations) and any changes you make can easily be undone.