I installed linux so i could continue using windows. when rebooting i got an error and "grub rescue" how do i get my computer back?

I am new to Linux, but I had a similar problem using a dual boot when the drive with the linux went bad and the grub bootloader stalled. In order to get to the windows OS I booted the system with the windows setup disk and used the repair option. At the command prompt, type fixmbr. This should cause the windows bootloader to be rewritten. It worked for me...good luck!

If you haven't got a windows set up disk, you will have to reinstall Ubuntu 10.04. Don't let it use the entire disk, go to manual installation and choose the partition that you original put Ubuntu on ( I'm assuming the installation won't install side by side with Windows.). This way you will at least be able to use Ubuntu until such a time as you can get hold of a windows set-up disk. When Ubuntu update manager starts to do updates, be sure to un-check Grub in the Recommended updates section. It was Grub that caused your original problem as you probably made the wrong decision as to which partition it should be installed in. ( The MBR,"Master Boot Record" gets corrupted.) I did the same thing!

 As for getting access to Windows 7 again, I haven't got around to getting the rescue disk yet, mainly because Ubuntu does almost everything I need! Windows 7 is good a lot better than Vista & XP, but it's not any better than 10.04 unless you're into PC games. This is my 5th year of Ubuntu and yes, I've experienced problems, but the community help invariably gives you an answer. So don't give up and give a good old whirl!

I hope this will help you:
Install your windows first by creating partitions
in my case i did like this:
1)C: and D: for ntfs...xp installed in c
2)i left abt 60 gb unpartitioned for ubuntu.
then
3)i installed ubuntu with /=15gb size
/boot=250 gb size
swap = abt double of my RAM size
and rest for /home

It working the best ...i am enjoying dual boot with no problem.

If you have a "Grub rescue>" message, it means the MBR (first sector of hard disk, modified by Grub) is unable to use the two first sectors of the Ubuntu partition. So you need to reinstall GRUB (for the moment, don't try to fix MBR).
This link https://help.ubuntu.com/community/RecoveringUbuntuAfterInstallingWindows will tell you how to restore Grub install. It not only restore MBR, but the whole boot loading chain.

Hello,
If your issue is closed, please mark question solved.
Else I should have some time next week to help you.