When I select "DOS" form the GRUB Menu I get the following messages in a black screen:

Booting 'DOS'

rootnoverify (hd0, 4)
chainloader +1

Remove disks or other media.
Press Any Key to restart.


Please Help !!!

Are you sure that the windows partition is in (hd0,4)? Check your current partiition locations with the 'fdisk -l' command. Might also need to hide the other linux partitions since Windows isn't on the 1st partition.

//Mod note: I'm moving this thread to the Linux - General forum, since it's more of a general purpose question rather than about using Linux in an Enterprise environment.

Thats the strangest part !! My Windows is in the first partition but the msg says "rootnoverify (hd0, 4)"

I tried re-installing Windows Xp using a bootable cd but it didnt work out some "bad function" error and to add to all this now my linux is gone too !!!!!!!!!

Please Help !!!

Depending on how you tried to re-install XP, you may have wiped the linux partitions. Try booting into rescue mode with the linux cd. Then do 'fdisk -l' to list all the partitions. If you don't see any that say linux (or linux related like reiser), then you likely hosed your linux paritions by reinstalling XP. If you still see linux partitions, then you might just need to re-install grub. Please post the fdisk output though.

If you did hose linux, then start from scratch and do it properly, format the disk and install windows first (leave room for linux and make sure to note where the paritions are on the disk). Then install Linux last and during the Redhat installation, make sure not to erase the windows partition, make sure it recognizes the windows partition during the bootloader installation screen (should show a list of partitions, including the windows one). If it shows windows in the wrong partition, you can simply change it during this screen or you can modify grub.con later.