device or resource not responding

My desktop is no longer able to connect to the internet wirelessly. At first I thought I needed a new adapter because all of my other wirless devices (cellphone, laptop, ipod) are all working fine.
I bought a new adapter and it still does not work. The adapters do however work in my laptop. I have followed several tutorials on-line. All to no avail.
When running the trouble shooter it either tells me that windows can't communicate with the device or resource or that the device or resource is not responding.
The desktop is an emachines running widows 7. The adapter is a Linksys AE1000 (however, also purchased the AE2500 and it also isn't working in this computer). The router is also linksys Wireless G -Broadband router, model # wrt54gs2 v1

 

Continued to search this site and someone else mentioned uninstalling McAfee. It worked!!!
This is the second time I have used this site to help with computer problems. The first was much more in depth. You guys are great!

 

Ive always used Avast over mcafee or norton etc. Never had any issues through anti virus