Need Help With Ethernet Controller!

For awhile, I had been having internet problems, I could not figure out what the problem was, so I decided to call my internet provider(Cox Digital Cable). We finally figured out, that my problem was I had accidentally uninstalled my Ethernet Controller, it had the yellow question mark beside it. So they had told me to download it from Dell's website seeing as how I have a Dell. Though, I cannot tell you what version it is, I am somewhat computer illiterate, but smart enough. I just don't know how to get the basics of my computer information. But anyway, my question being, can someone give me the link as to where I can download the Ethernet Controller? ((I can get my computers information, if someone tells me how, I can tell you, incase the Ethernet Controller that needs to be downloaded depends on version and type of the computer.)

Thanks in advance. :)