Hi zippimom,
Are you prepared to format your hard drive and lose all other data? How is your Hard drive partitioned? If you have had Win95 installed on the C:\ drive and dont mind losing whats on it:
1. Copy the contents of the 'Win98' folder to the D: drive (assuming you have one)
2. Create a bootable floppy for Win95. (Control Panel>Add remove programs>Boot Disk)
3. Restart the PC using the boot disk you just created. You should find yourself at the A:\ prompt.
4. Type format c:\
5. After the format is complete, type sys c:\
6. Restart PC, after removing the floppy from the drive.
7. You should now find yourself at the c:\ prompt. Type d: & hit enter.
8. At the D:\ prompt, type cd win98 & hit enter
9: When the screen prompt shows d:\Win98 you can type setup & hit enter.
10. This should start your Win98 installation. You can select the default options and keep clicking 'Next'. Keep the 16 digit CD Key (Should be on a sticker on the rear of the Win98 CD case) handy, you will need to type it in at a later stage.
11. BEFORE you do all of this, I suggest you find and confirm that you have all the drivers for your PC's peripherals, viz. Video card, Sound card, modem etc.
12. Post you experiences here at AnandTech! You can get more help, as & when you need it(you will have to use a different PC until you get it running!
13. If possible, get the help of your son's friend(s) or anyone who is comfortable with this stuff, should anything go wrong.(not wanting to sound discouraging, but its good to have a backup plan!)