youfoundjake - 5:54 am on Nov 4, 2010 (gmt 0)

Oh, also check power management for your nic cards, they could be getting turned off in order to save power.

Another thing to consider is that if you are using DHCP, I have seen Windows try and connect to a mapped drive prior to getting an IP address from the DHCP server or router, and of course a little box pops up saying "Unable to connect to network drives" but by the time you open up my computer and double click the network drive, the address has been obtained, and you are able to browse the network share. If this is the case, you can try a static IP address.