|I'm guessing you had the original hard drive (HDD) replaced. Is this correct?|
If yes, did they do a clean install of your system or did they do an image of the original on the new HDD?
Didn't whoever did the HDD replacement for you test to ensure everything worked before giving it back to you? (just an FYI, as a professional, I would not only have tested, but I would have taken a minute to show you it was all working and answer any questions you had).
Personally, I would talk to whomever replaced the HDD for you and ask them about your surfing issues. If it's a reputable shop, they will ask you to bring it in and look at it for free.