Droppin Internet Connection

I am using OS X 10.8.2 on an iMac 21.5 inch, Mid 2010.

For quite some time the internet becomes disconnected. I run windows XP via VMWare Fusion on which I run StreetSmartPro. StreetSmartPro continuously updates info from my brokerage account. When the internet is dropped, the messages I get on Windows are: "Local Area Connection: A network cable has been disconnected", "Error connecting to Main Server: Connection to trade server has been lost".

When I am running StreetSmartPro on Apple from Safari, when the internet connection is lost, the message is something like "internet connection lost: would you like to reconnect".

Yesterday I recorded the disconnects for several hours: 11:44 am; 12:09 pm; 1:50 pm; 2:41 pm; 3:23 pm; and 4:15 pm.

My Provider monitored the connection from their offices all the way to my computer for an entire afternoon. When internet seemed to be dropped for an instant, they saw no evidence. Their records showed that the connection was constant. His theory is that there is a problem within the computer.

Anyone out there with any suggestions?