Comment 5 for bug 535483

I had the same problem.

Symptoms:
fdisk -l displays what I would expect
parted /dev/sda print says "Error: Can't have overlapping partitions"
Admin-->Disk utility has my partitions, but tells me have 18446744069 GB of free space at the end of my drive

My brute force solution was to log back into windows (I presume like me the reason why this is a problem is because you don't want to have to reinstall windows), use the disk management utility: Start --> Run --> compmgmt.msc
Select the disk utility.
Removed all the partitions except the windows (Maybe I only needed to remove one, but I didn't have anything valuable on my /home partition so I removed them all)

Rebooted from live CD and now Gparted can now see my windows partition. Installed Ubuntu no problem

-Avi