windows 98 reboot loop after Format

Well a friend brought me his computer, i can build them, just not good at fixing. Well his problem was a reboot loop. He said the data wasn’t a problem. So i formatted and tried to reinstall Windows 98, and even after this there’s still a reboot loop. Well i figured the sasser worm maybe? so i downloaded the F_Prot antivirus program, since you can run it in dos, and everytime i run the program it also restarts the computer. I can run in dos mode just fine, but once it boots into widnwos 98, either at or just after the splash screen it restarts.