Your router will probably offer you security in the form of WEP or WPA encryption, depending on the make and model. If you ask this question again in the Network Forum, you will see lots of security questions for wireless networks (a fair few posted by me as I have just set up a wireless router/modem to give internet access to my PC and laptop. You should set up security, at best you might find your bandwidth being used up by others- at worse with internet banking etc- who knows?
if your wireless network is not secured by setting the encryption. If you are not sure how to do this ask by posting the question in the network forum as suggested by Debe. On my walk home from work I pass at least a dozen houses with open wireless networks in about two miles.
The big problem with open wireless networks is not file theft but bandwidth theft.
An open system can be used by others for all sorts of purposes - legal or otherwise. The hurtful thing is when you are on a capped sevice and you find that someone else has used up your month's allocation downloading what may be things you would rather not be associated with.
Hi herc182. If you are really worried about wifi security why not go to Ethernet cable instead, provided the cable run is feasable. Unlike USB, Ethernet cables can be considerably longer with no loss of quality. €dstowe makes the really valid point.
If you are only using your "wireless" connection for internet access, and not file transfers with another computer, unticking "File and Printer Sharing for Microsoft Networks" in the Wireless Network Connection's Properties will prevent access to your files.
However, you should still enable encryption and/or MAC address filtering to prevent your wireless broadband connection being used by others.