Yeah some routers are bull**** for anything other than web browsing and absolute horrible for P2P or Games, check for a firmware update and it might help slightly but what type of router are you using? Some can be flashed with 3rd party firmware like
Supported Devices - DD-WRT Wiki...
Sometimes Vista could be dropping connections but the conditions when it decides todo this are not common these days, wrong LAN Driver/CPU over-utilization or firewall/security software.