I have an old D-Link wireless router. I seem to remember a 615 in the model number. Occasionally I have to unplug it, wait a few seconds, and then power it up again for the wireless card to detect the router. I have called "Customer Support" several times about this issue. They told me that I am not supposed to have a firewall running on the computer. I am not comfortable with a computer connected to the Internet without a firewall, so when the wireless card does not pick up the router, I use the IT simple fix. If only the power down - power up trick worked for cars!

At the office, I am connected to the network with a Netgear wireless router. It is very reliable, although lately my computer has started flashing messages about signal strength weak/excellent out of the blue, while still connected.