Why won't my wireless security work?

Well and truly doing my head in!!

As soon as I apply any security whatsoever to my router my iMac will not connect to it.

My Windows laptop does it fine irrespective of whether there is any security on it or not but the iMac does not entertain it at all whether it be WPA or WEP.

Do you configure it from your PC? If so try the opposite and do it from your Mac via ethernet. I find it easier to setup from Mac and then do the PCs. Hope you find the problem.

Try putting a "$" at the beginning of your WEP key, then try to joing the network.

If that doesn't help, try these links from the forum:

http://www.mac-forums.com/forums/showthread.php?t=42135&highlight=wep

http://www.mac-forums.com/forums/showthread.php?t=42029&highlight=wep

On the screen where you put in the WEP Password be SURE to click on the Wireless Security clicker and change it from WEP Password to WEP 40/128-bit HEX. That solved it for me and a few others here.

Starting to annoy me TBH - I'm spending all afternoon fixing it tomorrow hopefully! People must be loving having free internet around my house

I was having this same problem the other day using WPA. I updated the firmware on my router and could not connect with my macbook using security. Rebooted my macbook and tried it again and worked perfectly. Rebooting seems to be the logical answer to a lot of problems anymore...I'd be willing to be you've already tried that though.