Before I start you should know that I am completely new to ubuntu. I have a Compaq Presario and Windows Xp installed on it. When i intalled Ubuntu i thought everything was ok but then I try to start my computer the only message that I get is:

GRUB loading.
error: no such partition
grub rescue>

My computer is stuck at this point. I need help getting my computer working again. I want to keep the my windows xp or fix Ubuntu. If anyone can help me it would b greatly appreciated.

If you haven't already use Super Grub Disk Homepage to repair bootloader.

Also if you are using Ubuntu 9.10 which uses the new Grub 2 bootloader instead of Grub 1.5

This Documentation link below will be of help

Grub 2 A guide for Users

Since you are new to Linux I would recommend the supergrub link instead though to fix Bootloader. Just posted the above link for any future readers of this post that may need documentation for Grub 2 Bootloader.

did you manually or automatically partition your hard drive for ubuntu space? READ THE LINKS THEY GAVE YOU!! lol....but iwas seriously asking that question though.