[snip]
Hi Daniel. As long as your c: drive is still in tact, you can boot the machine from a Windows installation cd (Dell Windows XP cd's work well as an example). After Windows loads it's files and you are presented with a blue screen with typically 3 options, at the bottom of the screen is a message like "R=Repair". After pressing "R", Windows will scan your hard drive for any existing installations. After that you'll get to a black screen with white text listing existing installations. If that works, select that installation at the prompt, then run two commands: "fixmbr" and "fixboot c:". This will rebuild the MBR and make your c: drive bootable.
Something like this ought to work for you as long as your Windows installation is still in tact.
Also cfdisk from a live Ubuntu CD has saved me in the past by recreating the partition table.