I had Ubuntu 11.10 installed with WUBI on my Windows 7 x64 computer. I wanted to install 12.04, so I just uninstalled 11.04 and installed 12.04 also using WUBI. When I ran 12.04 as a LiveDVD, I was able to access my Windows Hard Drive, but after I installed 12.04 my windows hard drive doesn't show up anymore and I need to access it. Any help with this would be greatly appreciated.
Open a Terminal (click Dash and search "terminal") and type the command
sudo fdisk -l
If you see a NTFS partition, that will be your Windows partition. It should also then show up in gparted or the included disk utility, from there you "should" be able to mount it and access your files.
Is there is a slight chance you erased it when you installed 12.04?