Pavillion Elite m9550 pulled hard drive - cannot start code 10

I have 2 identical HP Pavillion Elite m9550f computers, one for each of my businesses. One crashed and I really need some files that were on it. I pulled the hard drive and put it in an enclosure thinking I could open it, get the files, and put them on my new HP Envy desktop that I just purchased as the replacement computer. The new Envy could not " see" the external drive. Thinking that the Envy is running windows 8 and the Elite was Vista Home Premium and maybe there were compatibility issues, I tried opening the hard drive on the other Elite. The external drive was not recognized by that PC either. I found the device In the device manager, but there are yellow exclamation marks and the " This device cannot start. ( Code 10)".
Any thoughts on how to get my files off this hard drive, at this point, onto either the Envy or the Elite? Thanks!