Unstable Internet connection

It seems like my Internet connection drops every now and then when using XP in Parallels. (I have no trouble at all in OS X.)
When I click links or enter URLs in Explorer, sometimes I get the "Page not found" screen. When downloading, it stops after some seconds with an error stating it lost contact with the server.

I have the latest 3.0 build. I'm on a wireless connection.

 

Probably removing antivirus, or tuning it with correct settings will help

 

But I have not installed any antivirus software in Windows. (Have tried to, but as the connection drops, it's impossible to download).

 

Please create ticket in support