Limited or No Connectivity & Not a Valid IP Address

So I just bought a new netbook no less than 2 days ago from Best Buy.
My use for the computer doesnt require much, all I want to do is be able to connect to the internet at home, and use it at school for note-taking. For this reason I bought the Acer Aspire Netbook.

I cannot access the internet from my home network for some reason. It recognizes the network and it says i'm connected to it, but wont let me access the internet.
When I browse the network connection it says "Limited Connectivity" and depending on the way I diagnose the problem, it either says that im missing a wireless adapter or most commonly, that my IP address is not valid.

My computer was also running the internet very, very slow when I've connected at the school. I had a friend play around with it, and he actually downgraded some of the settings (or something), and it runs a lot better. But it still doesnt solve my home connection.

I've browsed many forums and tried a couple things, but im mostly scared to try the in-depth solutions (mostly because im not THAT computer savvy, and since I just bought the computer im scared to remove certain things just in case)

These are the specs:
- 1GB Memory
- 250 GB Hardrive
- Windows 7 Starter
- Model #: AO522-BZ499
- AMD c-50 Processor

I'm normally very good with computers, however im mostly a mac user and havent had a pc of my own in a long time.

And if someone does have an idea of how to fix the problem, can you please, in a lot of detail, explain step by step how to use that solution. I haven't used PC to this extent in a long time so I dont really remember how to search around the computer

Hi ifrong,

Please remove all wireless network profiles stored from your computer, then re-connect to your home wireless network, make sure that you have the correct Security key. Here's How.

Let's also try renewing the IP Address.
How to renew IP Address in Windows 7 | eHow.com

Please let us know.

OH my god, thank you so much, that worked perfectly! I was having so much trouble, and it looks like I was on the right track, I just couldnt find the simple steps. I really appreciate it! xD

Glad that worked out for you.

You're Welcome.