I have the same problem - it will not 'see' my Windows shares anymore, I have a few - 3- PC in the house, all running Win 7, all with shared folders with either music, videos, movies or photos. And none of them show up... well I should say that they will pop up sometimes on the screen for a second or two - and boom they're gone again.
I have Netbios over TCP on, static IP on 1 PC, DHCP on others.
It worked for a week or so, then I got a message that I had to reconned again, or simlar message.
I am thinking... could it be my router - I have a top of the line E4200 Cisco, runs great.
By the way my shares are visible to all and from all my other computers...
I did install the newest fimrware yesterday 1.07.15
Any ideas ?