NOTE THAT THIS METHOD IS ONLY RECOMMENDED FOR PEOPLE WHO DON'T HAVE A WINXP CD AND HAVE NO EXTRA CDS TO USE FOR BOOTING UTILITIES LIKE ULTIMATE BOOT CD OR SUPER GRUB DISK.
If you, like me, found yourself trying to uninstall [insert GNU/Linux distro here] by deleting a partition and you rebooted without restoring MBR on Windows XP, then you are probably familiar with the Grub Rescue screen that looks like the following:
You may think that it is the end of your whole life on Windows XP. Well, it is not. Hopefully, you have a LiveCD available, because in order to fix this then you'll need one.
Use a LiveCD/USB to boot into an operating system (preferably Ubuntu) and Install the OS.You may think of this as counter-productive, but it will end up being useful later on. The reason why you can't access Windows is because you don't have a bootloader to boot the OS with. Installing it will enable you to use the GRUB bootloader. After installing it, reboot and boot Windows XP and delete the partition you used again. Except this time use MBRWizard or MBRFix (for advanced users) to restore the Master Boot Record.
After doing this, you should be able to boot into Windows. If not, try looking elsewhere for some other information on your specific issue.