To see a PC directory from my box

Hi,

I've updated my PC from Windows XP to Windows 7 and my box from Pli 3 to Pli 4 and I can't access PC directories with the network browser. I don't know where is the problem, W7, Pli4?

When I use the network browser, I can see the PC but I can't access to the shared directories.

If somebody have an idea?

Thank you .