How do I remove Ubuntu 10.04 and GRUB from my Dell Inspiron M5010?

I recently bought a Dell Inspiron M5010 (the sticker near the keyboard says inspiron 15R (and in smaller letters M501R)) and tried to installed Ubuntu 10.04 LTS on it. Now I want to know, how do I remove GRUB and the Ubunutu and it's partition? I would just completely restore my system, but I don't have a boot CD because Dell didn't provide one for some reason, the one they did only runs diagnostics.