New Laptop stopped connecting to wireless network

My new laptop came on Wednesday, the 9th. It was immediately able to connect to my wireless network I had recently established. (I also have a desktop connected to the same network.) Anyhow, today, Sunday the 13th my laptop connected as usual but when visitors arrived I pushed the on button to turn it off - I know better but wasn't thinking at the time. After the visitors left I came back to my laptop, turned it on and it will no longer connect to the wireless network! I troubleshooted all I could and the only way I could get on the internet with the laptop was to use an ethernet cable - even then it was hard but can be accomplished. But it is a laptop and I don't want to leave it in one place all the time! I have access to Costco's Concierge Service and phoned them. He had me do everything in the book so to speak for more than an hour and it remains the same - no wireless connection!
I am wondering if my turning it off the wrong way could cause this trouble? I have never worked with laptops before but used many desktops and, even though it is not recommended, turning them off using the on button in a pinch has never effected my computers in any way.
Any comments or suggestions would be appreciated.

The laptop specs: Dell Inspiron 17R with Intel Core i5-2450M 2.5 GHTz, 8 GB Ram. and a lot of other stuff!

I do not know if turning it off that way was the cause of your connectivity issues, but as new as the computer is, you might want to consider restoring the operating system to the factory condition. Does it have a recovery partition on the hard drive?

Bd830 said:

My new laptop came on Wednesday, the 9th. It was immediately able to connect to my wireless network I had recently established. (I also have a desktop connected to the same network.) Anyhow, today, Sunday the 13th my laptop connected as usual but when visitors arrived I pushed the on button to turn it off - I know better but wasn't thinking at the time. After the visitors left I came back to my laptop, turned it on and it will no longer connect to the wireless network! I troubleshooted all I could and the only way I could get on the internet with the laptop was to use an ethernet cable - even then it was hard but can be accomplished. But it is a laptop and I don't want to leave it in one place all the time! I have access to Costco's Concierge Service and phoned them. He had me do everything in the book so to speak for more than an hour and it remains the same - no wireless connection!
I am wondering if my turning it off the wrong way could cause this trouble? I have never worked with laptops before but used many desktops and, even though it is not recommended, turning them off using the on button in a pinch has never effected my computers in any way.
Any comments or suggestions would be appreciated.

The laptop specs: Dell Inspiron 17R with Intel Core i5-2450M 2.5 GHTz, 8 GB Ram. and a lot of other stuff!

It sounds like something in the network stack was corrupted.

Save the file below, unzip and click on the file to run until your machine reboots.
After that please post a screen shot of your ipconfig/all here if you can. Of course you will need to save this file from one of your machines at home then move the file to your laptop first.

Chev - I have connected to the internet about 20 min. ago by installing and using the USB wireless adapter I was using on my desktop. It works very nicely even all the way to the other end of the house, something it would not do before it decided to quit yesterday. To me I feel it may prove the internal adapter in this laptop was not working well to begin with and then quit altogether. What do you think about that?
I have now run the IPResetALL.zip you sent but must confess I cannot find RUN from my start button! It was there yesterday but not now. I am assuming I need to use that area to get ipconfig/all for you to view. Of course I could be wrong about that!
I am now going to remove my USB connection and see if the file you sent did anything of interest. (I do know one thing about this laptop - the keyboard is really hard to use!)

It is still under warranty. I bought it at Costco and they have a 90 day return policy - the reason I didn't buy it directly from Dell. I will phone their Concierge Service this morning and see if they can fix it. If they can't to my satisfaction I will surely return it. They have a store just 2 miles from my house.
Thanks for you input.
BD