Everyone can connect to internet but me

Hey guys, I've run into a problem on my work today. There's a PC there that keeps turning off. So I got another old PC that works OK to replace that one. Fresh install of Windows 7. But there's a problem. My network doesn't seem to accept new PC's. Everytime I get a PC that's from somewhere...

So I want to ship several PC components, namely the motherboard/GPU/RAM, to a house in Tahoe where it will likely be snowing. These components will likely be left there for several hours by the door. These components won't be opened for about 7 days after delivery, so plenty of time to dry out...