I deleted win 95 then iwant to install win98

Indeed. If you have the windows 98 disc then just insert it into you CD rom drive and restart the computer. You should have the option of pressing any Key to boot from the CD. If not you need to hit delete a number of times when the machine 1st turns on to enter the Bios set up. In here you can change the boot order. Give your CD ROM drive the highest boot priority. Save & exit. Now you will have the option to boot from CD.

From here you are very much guided by the onscreen prompts. It's a straightforward process.