I'm stumped! Hardware, malware problem?

:confused My primary PC is an HP pavilion with vista on it. Every day, or several times in a day, my pc will not connect to the internet. I get "Cannot display the page Windstream.net." I go through a system restore, and I see that the last restore point was created when Windows was updated (I suppose by microsoft) I pick a point before the 'update" and the PC starts working ok then. Any ideas? And before anyone questions the number of PC's I've requested help with, I'm not a repair store nor do I work on them as a profession. I just love hardware, and it always finds a way to tear up. Thanks,

 

Working great now! Thanks MG!