Help Please I'm at my wits end here!

I just got a XPS 410 with Vista Premium I connected it via a USB wirelss adapter to my old HP upstairs in my house. I had everything set up fine and dandy file sharing printing the whole shootin match working great. The something bad happened . Now I dont know what if I did it or someone else in the house did it (wifw kids or dog), but I can no longer share squat no files folders or print. Nothing shows up and I can't find it or add it to my network. I'm in the process of backing up all my files and am thinking of restoring my computer to out of box condition. I set bit up once but I can't do it again. I just have some funny feeling it something very simple but I can't seem to pull my head out  to find it. Befor I go to the extreem of starting over anyone got an I dea for me?

Thanx