Your best option requires a second computer (or your computer with your other good hard-drive) with access to the internet, ISO Image burning software (or USB Flash drive compatible image creating software - see below), a DVD burner, and plenty of patience and time. Don't panic, that is the worst thing you can do.
Follow these steps and you should be able to see and backup your other files. BTW, I see you already tried the MBR Fix, which is what I would have recommended first.
1. Just hear me out - Download the Ubuntu Live CD (Linux distribution) from the Ubuntu downloads page. Google Ubuntu Live CD which brings up the following link: http://www.ubuntu.com/getubuntu/download The second hit on Google is a documentation site, which is also VERY helpful. That link is https://help.ubuntu.com/community/LiveCD The latter also contains a link to install a distro (Linux distribution) onto a USB flash drive, but this is only useful if your motherboard supports booting from a USB port.
2. Download an ISO Image burner and burn the Ubuntu image to a disk. I have found that IMGBRN works very well and is easy to understand. Google Image burn or click here http://www.imgburn.com/ NOTE: If you decide to use the USB version, you will need a 1GB USB Drive and a different utility to "burn" to the USB drive. I have used win32diskimager before. It is also recommended by the creators of Ubuntu (https://wiki.ubuntu.com/Win32DiskImager). Google win32diskimager or follow the link from the Ubuntu website.
3. When you have downloaded the ISO or USB image, launch the respective image burning utility for your media (either IMGBRN for DVD or win32diskimager for USB) and create your bootable media.
4. Insert newly created bootable media into the computer with the bad boot sector
5. Go into your computer's bios and make sure your type of bootable media is active (Since you talked about booting from XP CD, I will assume that you know how to do this)
6. Start or restart your computer, making sure you followed steps 4 and 5 above
7. The Ubuntu screen should show up with a loading type screen - just be patient
8. Once in Ubuntu, you will see an almost overwhelming screen that is similar to windows. Your hard-drive partitions should be listed on the right, assuming you booted to Ubuntu from the computer that has the bad boot sector. You should be able to back up the files here, and then wipe and repartition your hard-drive (start from scratch).
I know this does not help you avoid a fresh install of Windows, but it will help you recover your other files.
Hope this isn't too confusing! I am exhausted and tend to ramble.
Post back with any questions; I will follow up if needed.
bw
