I was gonna ask about that "WMA"? :D
Maybe Windows was allowed to install an incorrect wireless driver in both those PCs? If you can roll back the driver try that. And/or install the latest wireless driver (from the laptop manufacturer's web site if an integrated adapter; else from the adapter manufacturer's web site).
I suspect the router, but mention the above because of the possibility of a problem with both PCs.
Make sure you have the latest router firmware. Then reset it to factory defaults and reconfigure it.
Assuming that does not fix the problem you can replace the router or you can wait until the router refuses to play nice with more devices and then replace it.
Maybe Windows was allowed to install an incorrect wireless driver in both those PCs? If you can roll back the driver try that. And/or install the latest wireless driver (from the laptop manufacturer's web site if an integrated adapter; else from the adapter manufacturer's web site).
I suspect the router, but mention the above because of the possibility of a problem with both PCs.
Make sure you have the latest router firmware. Then reset it to factory defaults and reconfigure it.
Assuming that does not fix the problem you can replace the router or you can wait until the router refuses to play nice with more devices and then replace it.