I have a window 8.1 and i try to install Ubuntu on window 8.1 that may be overwrite my hard disk data .and now hard disk doesn't show any data .when i connect hard drive externally on other laptop .Hard Drive doesn't shown .but it shown on disk management. How to show external hard drive on window 8.1 with out formatting the data.
When you install Ubuntu on the hard drive, judging by your case, you most probably chose "Erase disk and Install Ubuntu" option when you installed. Assuming that, your hard drive is now (most probably) partitioned into 3 partitions - EFI, swap and Ubuntu partitions. Ubuntu is formatted using "ext4" file system, which is not recognized by Windows 8.1. Hence your hard disk appears as a blank, unallocated space.
P.S: You have most probably lost all your data. If I were you, I'd try to use a file recovery software (from inside ubuntu, to avoid overwriting more data) and try to recover some data. I've been in the same situation and this is from experience.