Computer problem - being hacked?

My pc has been playing up for a few days. its ok at first then after a while the internet stops working properly and i get error messages "internet explorer cannot find the page" - sometimes on only parts of the page, while other parts load ok. but google always works fine?! restarting the computer seems to return things to normal, for a little while at least. i have got a wireless router to enable my housemate to use the same connection but my pc is wired in - its not wireless. i have got up to date norton. some guy at a computer shop said it sounded like it was being hacked? this has scared me half to death! what does anyone else think?oh and to add - my mate using the same isp but wireless is not having any such problems. leading me to think its not the internet connection?
Answer
Try scanning with an anti spyware program ____ http://www.ewido.net/en/download/