wireless network died!!!!

Well, I had my network up for about 2mos with no issues. Then I had a problem...my wireless would only sometimes connect. 2 desktops same location. so I thought it was my NIC so I swapped it. then I changed 3 routers out and another 3 NICS same result. But, bring your laptop over no issue. Plus, started with a linksys, then belkin, then back to lynksys, yet the router works great. network card I can put in another PC....different location completely and works fine yet little or no connectivity. I have gone so far as to unplug my microwave for those of you who know what I am saying. I have not added any new devices to disturb the connection. any ideas? or should I call my provider to install their stuff so its their prob? hehehe. but I hate to spend the money.thnx for your opinion folks