I have a MacBook Core 2 Duo with 2 GB RAM. Lately (past month) I have been having some problems with my wireless connection (which occurs no matter what wireless network I am using). When I turn on the computer the wireless download speed is fine. Then, after I have been using my MacBook for a while, the speed begins to fluctuate. If I am downloading a file, the progress bar moves along at a normal rate for a little bit and then stops and then it continues to move along again at a normal rate and then stops and this continues until the file eventually finishes downloading. This occurs no matter what application I am using (i.e. Safari, Firefox, Download a file from my iMac over the wireless network, iChat, etc.). The progress stops about every 2 seconds. The only way to fix the problem is to either shutdown and restart or to just restart. Then things work fine again for some time. It doesnt seem to happen when I am doing any particular thing or using particular software. I contacted Apple Support and they had me make some changes to the network and wireless settings (i.e. create a preferred network for my wireless connection, delete some network wireless Library files, repair permissions) and then when I rebooted the machine, it was, of course, working fine while I was on the phone. However, later in the day the problem reappeared. I was using Tiger and upgraded to Leopard on the weekend hoping that it would magically fix my wireless problems but it hasnt. I have installed all of the updates as well. I am hoping that this sounds familiar to someone and there might be a fix for it. I have been looking online for an answer for quite some time. Rebooting my MacBook all the time is driving me absolutely crazy!!! Any help would be greatly appreciated. Cheers.