Windows 7 networking problems

I've had this particular SMC Barricade G wifi router (SMC2804WBR) for several years. In November I bought a new HP PC from Sam's Club. It came with Windows 7 Home Premium. Once I connected it to my network it started causing problems. Every time a wireless device would connect to the network the Windows 7 machine would report no connectivity. The only solution appeared to be restarting the wifi router (by unplugging and replugging). I eventually reconfigured some of my devices to be hardwired and repeated the restart process with each of my remaining wifi devices. Things seemed to settle down until my daughter and her husband came home. Now, once again, every time she turns on her laptop or he turns on his (wifi) desktop the network is killed and I have to restart the wifi router. I've tried looking this up but all the articles that I can find in this vein are old and refer to the beta version of Windows 7. Now that they have been home a couple of days the problem appears to be getting more infrequent but it still bothers me. Shouldn't Microsoft give some explanation and a better solution than restarting my wifi router for every new wifi device?