Can Wireshark help me diagnose frequent broadband disconnects in Win7?

This is a newbie question. I run Win7 Ultimate and for months a reboot takes up to 5 mins + to connect to the net. It also disconnects randomly throughout the day and eventually reconnects on its own. If not Wireshark, what do you recommend I use to find this mind-numbing sucker? I use a Netgear Modem/Router and have been through everything I can think of.

Many thanks.