I have had Win XP on my system for a while. I just installed Mandriva on a partition of the 250gb drive. Once setup was done, the computer restarted. Although, XP booted. It did not give me a choice of OS. I was wondering how I load linux.
Please Help!

You should have made a boot disk for Linux during installation, or, you should have written stage 1 of grub to the MBR (the rest would be in the /boot directory of Linux). However, all is not lost. You should be able to put the installation cd/dvd in the drive, start the machine, and boot from installation media. A well behaved distro will offer you the choice of booting from the kernel image on the cd/dvd, or boot from the hard drive.

Once booted into linux, you should install grub to the MBR (search these board on the keywords 'grub' and 'dual boot'. There are many. You could also use www.google.com/linux to find grub installation instructions.

Bear in mind that once you've done that, you will probably have to manually edit the /boot/grub/menu.lst to make an entry for xp, in order to be able to see in as an option on the grub menu, and to boot it. There are many posts on these boards on that issue as well.

I was not able to boot from the cd. It only allowed Instal. When i was installing i did not see a option to create a boot disk. The whole GRUB thing sounds quite confusing. I got a HOWTO ( http://www.geocities.com/epark/linux...w2k-HOWTO.html ) I may wind up following this if i can not find an easier way. Is there some way I can disable XP from being the default boot OS?

Apparently Mandriva doesn't qualify - especially in light of the OPs follow-up post. I had Mandrake 10 chew up my part table, forcing a total rebuild - swore never to use Mandrake again. Doesn't look like things have improved much.

VIR3NT:
The install should have installed a Linux boot-loader (or at least offered the option) and automatically found XP, and put an option in the boot menu so you could choose either. Every GUI installer I've seen does this - or at least attempts to.
Your situation can be fixed, but requires knowledge you appear to lack at the moment. Even to follow that link you posted, you need to know where the Linux boot-loader was installed.
Grub is a *much* better option, BTW.

My advice - get another distro, and try again. If you insist on Mandriva, try the forum for that distro, here on LQ.