Can't download ANYTHING on Vista and never have been able to. Running on a Dell inspiron 1525, I always get the message: Your security settings do not allow. In other words, "Computer says NO". I have tried turning everything off, and using the lowest settings, but still no luck. Even disabled the firewall and defender (that makes me nervous). I am about to chuck the thing out of the window.
Sounds like it could be a virus. On another computer, download Malwarebytes Anti-Malware and install and run it on your computer. The free version is fine. Remove anything it detects. If the installer won't open, try right-clicking it and click "Run as Administrator". You've been helped by a 14 year old.