I can't help you with your problem as I never came across that error but I'm going to chime in. Please update your operating system to Windows 10. You don't need a new computer to do so; though this depends on your actual hardware specifications. Vista and other older versions of Windows are hugely insecure; and the fact that you're installing a bitcoin wallet on your Vista device, is a huge no no.

If your computer can't run Windows 10, go with Linux. It might not be as stable as Windows, but it's stable enough in my opinion. Take a look at Linux Mint and Ubuntu.