9300i Looses Connection with PC

Hi there,

Nokia 9300i

My phone sometimes looses it's USB connection to my PC. When connected
to my PC, sometimes with the cable and sometimes through the docking
station. When connected, the screen shows the USB icon as well as a
"U-shaped" icon. Then after a while, this U-shaped icon has disappeared
and I cannot use my phone to connect to the internet.

What can I do to fix this?

Regards,
Deon