Open the Programs folder, then go to the Startup folder and look inside. Drag the icons of the programs you don't want to launch from the Startup folder and onto this new folder. Restart your computer, and the programs won't be running. If you want to run them manually, launch them from the new folder on your desktop. You can check here by using Sysedit, a configuration file editing utility.
Some programs are harder to track down.
Click Start, Programs, Accessories, System Tools, then System Information. Go to the Tools menu item and click on System Configuration Utility, then click the Startup tab. From here turning components on and off is a matter of clicking a check box. To me, this application alone is worth the price of upgrading to Windows 98. Again, let me emphasize that if you are unsure about making any of these changes, then don't make them.