I would get a small pocket knife or nail file and lightly shave off some plastic on the connector, so it fits better. I know someone who bought an iPhone case that didn't let the charging cable fit quite right, so she did the same thing and uses that case all the time now.
I advise getting a new computer [or borrowing someone else's] and a USB to USB cable, plugging in the cable from computer-to-computer. That way you can see if the contents of the hard drive are still there. If they are, it's probably a connection problem. If nothing shows up, the hard drive has gone bad and is unusable.