I am using windows vista with IE8.Recently I am getting error message whenever I do Internet & type web address in browser.Erros is DNS error,server cannot be found link may be broken.I am not able to access sites sometimes,Most of the times I do.

I also do system restore,But issue is still same.

What's the problem with my system.

Pl advise?should I go for operating system Reinstallation?or use FIX IT Tool to resolve it?