Thanks for the help. I'm going to start over like you said.

Invalid Partition Table ... and the fix I used.
 

Not sure if you solved this issue or not yet, I'm a new joiner to this forum and just noticed your thread.

I shrunk my Windows XP partition using Gparted (LiveCD), then messed around installing various Linux distros on subsequent partitions.

Everything was going fine until I attempted to install FreeBSD on top of my Ubuntu (basically I wanted to replace Ubuntu with FreeBSD for learning purposes).

I'm sure it was my error, but somehow I messed up the boot loader that I had previously installed OK.

Then, through another error (watch out for those componunding errors :-), I used a Windows XP CD (recovery console) and the Fixmbr command (probably a mistake).

The Fixmbr command appeared to be the cause of my "invalid partition table".

Fighting a panic urge, I searched around and finally located something called "Testdisk", which claimed to be able to scan a disk and rebuild a partition table.

This comes with various rescue CD downloads; the one I chose was at http://rescuecd.pld-linux.org/.

Using the instructions provided (and lots of Googling), I was able to restore the partition table so that I could at least boot from the original Windows. Nothing was disturbed on that install, which was nice. I had a backup, but wanted to see if I could recover without.

Sorry if this post is long-ish, but wanted to give you the background as well as the info. Hope it helps.

interesting that the "fixmbr" didn't work.

normally, that would overwrite the 2nd copy <backup> of the fat to the 1st copy. <main>.

then, you would normally, overwrite that, with grub.

Unfortunately, I have been spending a lot of time recently recovering inaccessible NT partitions using the microsoft boot/install OS CD (menu option R).

I have noticed the fixmbr works only in a minor confusion of a disc table.

It has been useful for me to use chkdsk/r in this mode. If worse comes to worse, you can try bootcfg/rebuild (you probably will need to say yes at the next prompt).

It goes without saying that your data had better be backed up before you attempt the above.

If you wish to play around with multiple distros as I have done (since I am also a newbie with linux); my suggestion is this: pickup a few used 20 or 10 Gig Hard Drives and just swap them out as need be.

I find that dual boot makes more sense when you land in a distro you are going to use on a daily basis. Or create a small Windows 2000 partition first to check out the dual boot.