Re Installing XP on a dual boot system

I am facing a kind of problem in a dual boot system...Initially I had Windows XP(SP2) and Scientific Linux 5.1 in my dual boot system...and the default bootloader was grub. Now due to some virus problem I am forced to fomat the NTFS partition where previously windows were and re-installed XP on the same existing partition. I didn't touched any other partition during installation. But I forgot to note down the partition where linux is installed. I have the bootable XP cd and one ubuntu live cd. Is it possible to bring back the previous dual boot state(i mean the boot screen where it prompts for linux or windows..and so on...)without effecting the existing linux in the system? Please refer the solution along with the code also.Please tell me how to see the existing linux partition and where n how to install grub.

Thanks and regards.

FUTOSKOPE

Do a search in this forum for installing grub.