It depends on the number of applications still running and the number of processes (tasks) running in the background.
In Windows 98 press Ctrl+ALt+Delete. Look at the list of running tasks. Do you have quite a few listed?
When I do the same on my Windows 98 machine I have just three entries when I start my computer:
PC-Cillin background monitor
You should not have many more than this.
If you have a printer installed that will add another entry and you might find Rnaapp in the list if you use a dial-up internet connection.
To get more information go to the start menu and click on run. Then type msconfig. Go to the startup tab in the window that opens and see what programs are starting up when you load windows. You can deselect the entries you don't need.