Q: A reader of Windows 7 for Seniors writes that she uses a USB adapter (or dongle) to connect to a wireless network. The signal is strong for a laptop but a desktop PC shows a weaker signal.
A: Get a USB extension cable long enough to let you move the adapter around to see if you can find a stronger signal. (These cables are very useful for easy access to ports that are out of reach.) The PC may be physically interfering with reception or producing a conflicting signal. Microwaves and cordless phones also can interfere with older wireless devices. If your PC has USB ports on the other side of the box or on the monitor, try those ports, first.
If this suggestion doesn’t help, some adapters accept add-on antennas.