How reset boot option 4 Linux & Windows

Hai ,
I instaled win98,WinXP & Linux in my system,at last i instaled linux so it asked boot option for all os,resantly i reinstaled my Win98,after that the boot option is not come.I can’t boot my Linux ,i had boot flopy for linux and Windows but i don’t know how to reset my booting option for all my 3 OS,