Hacked from the Inside

Hi.  I am so thankful for this forum.  I have a NetGear CG3000D modem and a seperate Cisco modem for the telephone line. This post concerns the NetGear modem.  I have two computers, Vista HomePremium and a Win7 both are directly wired to the Netgear modem. I have control over this modem and have changed the password and SSid etc.   I have allowed a friend of mine to use the wireless to my modem and have given him the SSID and keyphrase.  He does not have the password to access the modem to make changes (that I  am aware of).  He is running Win 7 on a laptop using wireless.  My questions are:

1.   in the lower right hand task bar on both my computers, he shows up as:   "media player has discovered Joes-HP."  When I open media player,all my documents and files, pictures,videos are showing up in the player.Is this normal?

2. My printer quit working on the win 7 & and never shows up in the network map.

3. The Netgear modem does not show up in the network map but on occasion.

4. I feel as if I am connected to his laptop and not the internet.My computer will get really really slow.

5. I have files deleted.

6.I disable all of the Remote Services in Services,and they end up tuned back on to automatic. 

I downloaded TCPView and his laptop showed up as a remote address.  Also showing up is a apple device

which he has and I dont.  I think he is cloning my mac address as well.

Is he accessing my computer and controlling it?

Thanks for the help

thanks for your help

ur h

thanks all for your help