Hi,
maybe your PC won't work with your because your PC does not have USB 2.0 or so, but this is not likely the case unless your PC is rather old.
If your PC can use the external HDD, it most likely won't mount the Volume on it (that's where the files are), ceause it is formatted as HFS+. Windows isn't capeable of HFS+, so you won't be able to access the files unless you use some tool/driver, that makes Windows read the HFS+-Partition. I have seen a commercial of MacDrive, but I guess it's not free. You can google for another free tool. You could also use Linux, which I think has HFS+ compatibility.
I hope I could help