Your computer can get bogged badly at startup and effect the way it operates the entire time it runs after a bootup. There are several ways I've heard of, seen, and done to do this. As of now I only use 2 programs to do it and they work very well. Almost nothing runs on my startup that I don't allow. One program I use is Spybot S&D 1.5 and Tea Timer which is bundled with Spybot. Tea Timer guards almost all startup entries from registry entries, to Startup folder entries, and to scripted program entries like installing a new program might do. Tea Timer can be set to ask if this new entry is allowed. Even if it was allowed before Tea Timer was installed on your system you can go into settings and remove an entry from startup. As I've seen where MSN and Yahoo can rewrite themselves to startup Tea Timer is perfect at keeping it from doing so. You can remove both those entries with msconfig in Windows but once you open either program again they are rewritten and reallowed to starup without something stopping them.
There are a few programs that add entries that I've noticed that can be added that Tea Timer can't see. For these I use Windows Startup Control Panel. Perfect for a lot of AOL entries that I've noticed that Tea Timer can't see. Windows Startup CPL can keep all of AOL's entries from startup and most of Window's default startup entries that come with certain hotfixes from Windows Updates. Both programs are pretty easy to use and very effective. And just so you know I can reboot, log online (using dialup), and be back in the room on WinMX in just under or around 4 minutes, and I consider my shutdown fairly slow, lol. If anyone knows any other good and effective ways of controlling startup feel free to post them here. That's what it's here for.