with one of the other wireless Macs and see if it can talk to the mini.
If it can, then the wireless on the Mini is good.
My Mac mini 2.0GHz :120GB (early 2009) purchased March 2009 doesn't recognize my Apple Express Router anymore.I'm running Snow Leopard OS 10.6.4 My other Mac computers in the home don't have a problem. I think I have a hardware issue? It might be my airport card? What do you think?