[newbie] Installing WinXows again

[Riker]

Hi:

Do to the poor quality of a certain operating system, I'm having to
reinstall it on a duel boot system. Linux is still running great (both
were installed on the same day) and I don't want to lose it, but given
the nature of WinXos, I will lose LILO and GRUB. After reinstalling the
other operating system, how do I put my friend LILO and GRUB back in?

I know this involves booting with the boot disk, but just not sure what
cammands I need to run to get Linux back in control. 

Thanks,

Riker