I have previously used my 1TB hard drive as a backup for my Mac. I have now since moved on, but cannot access this under the “my computer” tab on a Windows PC, although the PC recognizes it is plugged in.
Jan F's advice is solid, and I won't attempt to add to it. I will say that a much simpler method may be to visit a Mac-owning friend and grab the files using that machine. Could save you some headaches.
Most likely the drive is formatted in OS X native file system HFS+. To access it under Windows you either need a file system driver or you could use HFS Explorer
If you used Time Machine to backup your Mac you should be able to access the Sparsebundle using HFS Explorer or via e.g. 7zip.
* I haven't tried that myself so their may be complications or issues since TM sparsebundles are usually locked via the username and password I don't know if they are needed or one is even able to supply them when accessing via Windows
There's an excellent article on this very subject at: http://www.pcadvisor.co.uk/how-to/windows/3369574/how-read-mac-os-hfs-drives-in-windows-for-free/ .
In a nutshell, you can use HFSExplorer, which is free, to read your data. If you also want to be able to write to the disc, buy Paragon Software's HFS+ for Windows 10 ($19.95).