I have a secured linksys wireless router in my house that has always worked fine. Just in the past week or so my laptop now drops connection every few minutes. This computer is not idle when the connection is dropping. Also I have noticed that right before my connection drops I will often get a popup on the wireless connection icon that says "Wireless Network Connection is now connected - Linksys (unsecured)" -- this is odd because this IS a secured network. About 5 seconds after the message pops up the connection drops and I get the "cannot connect to preferred networks" message. I can then reconnect fine and the laptop will stay connected again from anywhere from 5 to 20 mins. I also have an iphone that I often use to connect to the same router and it never appears to drop which leads me to believe that the issue is with the laptop. Any ideas on what is causing this? Thanks!

First I would suggest to install all the latest Microsoft patches and latest driver version for your laptop.

Now that you mention that, it seems that this problem started around the time that I installed the latest windows updates a few weeks ago. I just installed the latest updates again today and this did not correct the issue.

How about the Dell drivers? All the latest drivers installed?