Is somebody "sharing " my internet connection/network/computer?

NIS 2010 17.8.0.5

Vista Home Premium 32 bit, Vista SP2

Desktop PC

DSL connection

 

Only 1 computer, no laptops, no wireless connection

 

OK old habits die hard

 

I'll admit I was looking at the Firewall and Internet Connections History

Ran across something that concernes me

 

Seems like when Iogged on this morning there is an entry in this history that says

"Connected to a shared network"

Then gives six pairs, some a letter and number and some just pair of numbers.

(looks like this though not the actual pairs   55 82 A6 C4 31   4D)

 

As I said I only have 1 computer

When I check Norton Network security Map, it shows only my 1 PC in network

When I check Task manager, Under Users just shows 1 (me)

 

So what does this mean? Is someone logged into my  internet connection?

 

Some one hacked into my machine?