Natsufire

Hey guys, I tried to connect my IPad 3 (I.O.S 9.3.5) to my HP laptop after installing ITunes to be able to download Vshare onto my iPad, however once I plugged my iPad into the Laptop an error message popped up on iTunes which said "This iPad is supervised by another computer and cannot be used with this computer.". I tried searching for remedies online and tried to put my iPad into recovery mode (after backing up my iCloud) and then plugging it into the computer and restoring it but even this didn't work. After this I tried rebooting the PC and uninstalling and reinstalling iTunes to see if that had any effect but it didn't. I've had my iPad for years and I've never had this problem, and I'm not sure what this other computer is. Is there any way to fix this? Thanks,