Small problem with Wireless Network and iMac

Okay, I have Optimum Online and a Linksys WRT54G Wireless Router, and the Network is running fine. I have three Windows machines that run normally. Now, whenever I power down and start my computer up, I lose the internet connection for some reason and have to use the Network Diagnostics EVERY TIME I restart. It doesn't take that long, but it's kinda annoying. How can I fix this? I'm using an iMac 17" Core Duo

What sort of crypto/enc. are you using?

If you're using a flavor of LEAP, try this:

Set the encryption to WEP.

Then, in the passphrase, put this:

<username/password>

(make sure you include the <> too

I had that problem, then after I did that, it was no longer an issue.

... what? sorry i don't get it... which username? my iMac username?

bump still don't understand what i have to do.