Windows 7: How do I fix my internet connection for Xbox Live?

Hi everyone, I'm totally new to the forum and I've been having this issue for over 3 months now.

I can't connect to Xbox Live... no matter what I try to do, nothing works. Well, recently, I think I may have stumbled upon the solution:

Open Network and Sharing Center -> Change Adapter Setting -> Right click on local area connection -> click on Properties -> click Sharing -> Mark everything up and choose my Wireless Connection.

However, when I hit 'Ok', this message pops up: An error has occured while internet connection sharing was being enabled. The dependency service does not exist or has been marked for deletion.

I don't understand what any of this mean... anyone have any clues? And is this even the right way to go about my problem?

It says my Xbox live connection is an Unidentified Network with no internet access.

Anyway, I'm not exactly tech-savvy whatsoever, so yeah...

Thanks in advance if anyone can help