ok 1 last test before trying a network tool I have,
if I get this right the problem on the user account is intermitant, if so do the following test and post results back up like before taking a screen shot,
go to command prompt and type the following command
ping 173.194.67.94 -t
go to google ca and keep loading and refreshing the page this will trace any breaks that you have in connection and then the test will tell us why,
and at what point the connection is brocken, upload the results I will give you some software to download.
what i am doing is pinging a constant ping to google untill the problem happens and monitoring the response times also it would be worth checking in event viewer and finding out if there is any information there, I will also wright you some software you can use to do further testing and reports,
Let us know how you get on.
Kind Regards