Well, you write that "In fact it can't even read the partitions correctly..." which tells me that at least your BIOS sees the drive. I might run e2fsck
on the unmounted hard drive's partitions that you want that ~/ data from. Just to check for anything weird.
The only difference between ext2 and 3 is journalling, and maybe some driver enhancements. ext3 is completely compatible with ext2. You can even mount ext3 as ext2. Same file system structure on the drive. Ya know....Anyway, raw gave you a quick fix, and (s)he's got a point about little information provided.
I routinely add hdd's to my working Debian box upstairs (Ubuntu is based upon Debian): NTFS, fat16, fat32, ext2, ext3 -- reading them is never an issue. I do this to save or backup data for neighbors, customers. It should be a no-brainer -- let us know.