LinksysWRT54g connection issues

Hey guys, I recently setup a Linksys wrt54g2 for some friends and it works great so I decided to get with it and get myself one. Well after changing the ip of the router and doing an ip renew/release and rebooting, it's worked fine for weeks.

I just noticed today that the desktop which is connected to the router via Ethernet has no internet connection at all. The laptop's wireless connection is still fine and has internet access,etc...

I'm a bit rusty at network troubleshooting and have been doing some research but is there something obvious I'm missing?

BTW, the reason for changing the router ip is that using the setup CD, the Linksys install 'wizard' could detect my internet connection (DSL) for some reason...

EDIT: Forgot to mention the rest of the issue: Ok so I removed the router's power cord for 10 seconds, plugged it back in and after doing this a few times (as prompted by the 'Network Magic' wizard app) suddenly the desktop connection was repaired, but of course, now the laptop connection was lost and though it has full signal strength, there's no wireless connection. I don't understand how this router could be acting up, it hasn't even been turned off so I don't get what could've scrambled its settings.

 

Sounds stupid, but is the ethernet cable plugged in securely into both computer and router. Verify!

What OS is the desktop running?

There should be a network icon in the system tray; does it have a yellow exclamation or red X?

 

Both the desktop and the laptop are running XP SP3...ethernet cable from the desktop to the router is secure. In fact, I've used the desktop maybe once or twice since setting it all up.

The laptop's tray does have the lan/! 'limited or no connectivity' icon. I tried a repair but it finally came back, 'the following action cannot be completed:Renewing your IP address'.

And just in case I sounded confusing above, basically everything worked fine, then desktop lost internet access, unplugged router power, router was able to repair its connection but now no wireless laptop connection. Nothing on the router or internet connections on either computer were ever touched.
BTW, the laptop is configured to obtain an ip automaticallly...

EDIT: Well, I hate when it works this way but I got it working again...after trying various settings to no avail, I shut down the desktop, unplugged the router for a few minutes, unplugged the modem from the router and then powered up the router, plugged in the modem and let it sync w/the router, turned on the desktop and it was working again. I hope this WRT54g2 isn't going to make a habit of this....

Thanks!