Hello and welcome to the forum.
First you will likely want to confirm that the problem is not with the wireless adapter in your Dell. Test at a local hotspot or coffeeshop, McDonalds, etc., Just to make sure that the adapter didn't coincidentally shoot craps.
Once you are certain that the problem is not with your Dell then you'll need to experiment with your network appliances. May as well start with your router... make sure that you turn off any MAC or IP filtering, set the encryption to none or open temporarily for testing, change the channel to something as far from the one you are using currently as possible and then experiment further by switching to (1, 3, 6, 9, 11).
Open a command prompt and type
ipconfig /all > desktop\ipconfig.txt
This will put a text file on your desktop, attach it to your next post.
Regards
Randy