i had the this same exact problem. in order to resolve this, they say you have to disable spi in your router. it has something to do with vista's tcp window scaling not being compatible with most routers. although sometimes that doesn't fix it completely. for my router (linksys rv042), i had to disable the router firewall completely and i no longer have connection problems. try either one and see if it works for you. as soon as linksys updates their firmware for the rv042 to support tcp window scaling, i should be able to enable the firewall again.