You probably have some malware on your system, or more specifically your log on or user account. I personally don't like the idea of disabling all sartups thru msconfig--if you have an always on connection (Dsl, cable,etc.) when you reboot you'll be on the net without any antivirus or other protection and it only takes a few minutes to get infested that way. It would be better to leave your security apps running and disable startups one by one til you find the culprit.
Actually there are much quicker ways. HijackThis is, in a way the ultimate startup manager. Malware, and some legit items, finds several ways to start that won't appear in MSCONFIG.
Follow the instructions in this tutorial to get a log posted:How to post a HijackThis Log
We can usually pinpoint what the problem is fairly quickly this way.
Or if you like, you can open Task Manager (Ctrl+Alt+Delete) and click on the processes tab. What seems to be taking up the most CPU and memory (besides system idle process)? Now click the performance tab--is the CPU maxed out?