Windows Protection error on startup

I have recently upgraded my old Compaq Presario PC from Windows 95 to Windows 98FE. I checked Microsoft Knowledge Base and get only one solution and it does not work. I get the following:
After you upgrade Microsoft Windows 95 to Windows 98 and restart your computer, you may receive the following error message:

Windows Protection Error
You must restart your computer
Your computer may then turn off automatically.

What other solutions are there?