Hmmmmmm....Vista preventing access to chat? Never heard of that one....yet.
Although....I've never heard anyone speak fondly of Vista, either. (And I know a great deal who have it). Those who have it and know how to reformat to XP, do. And those who don't know how, regret it and suffer.
Have you heard, though....Vista is now Mojave?

btw....there are many ways of troubleshooting your issue. Have you tried to google it to reach a site that can assist you to finding the problem?
I'd try to help, but I have XP.....not certain if I could be of any help to you. I'll keep my fingers xed for you though. Hope it works out.