I have a machine which has 2 operating systems. One is windows Xp and the other is windows Vista. First I had only Xp. Then I installed Vista. Now, I have a option coming.. either to select Xp or Vista.

I have to install linux by removing the Xp. and Vista stays there. Xp is in C: drive and Vista is in D: drive. (MS convention). The bootmanager is in C: (I checked it with some software).

C: Xp
D: Vista
E: My Data

If I directly install linux by choosing the C: drive, will there be any problem booting into Vista??
Will the GRUB show two OS after installing linux -- Debian and Vista ??

What should I do to install Linux on this machine?

Thank you.

Take a look here. There are various dual boot howtos for different situations. You can let grub do the work or re-install the Vista boot manager. The only doubt is an ancient rule that "windows wants the first partition on the first disk" but I don't know if it is still valid. Maybe someone more experienced on Windows/Linux duals can be of more help!

The clean way to do this is to first install Vista to the first partition---or to a completely clean disk. Regardless, give Vista maybe 15-20GB, and leave the rest of the space empty. When you install Linux, you will create a new partition in the empty space. The typical installer will automatically detect Windows and set up the GRUB configuration.

I don't know what happens in your case if you simply remove the XP partition---the Windows MBR boot code transfers control to NTLDR, but I don't recall if thats in the first 63 sectors of the drive, or in the partition. There are probably some simple ways to test this.

Don't forget to backup your data before trying any of this.