how to I turn off internet access

? could you elaborate on your question because you didn't hand a lot of info.
 
 

Hi ? and welcome to the Webroot community.
If I may add to the conversation,
 
Depending on what you are trying to achieve, you can block the internet in several different ways.  Listed below are just a few.
 
Some of these will isolate your system allowing you to continue to work but you will lose access to the internet and local lan (including networked printers).  None of the following are destructive.  Worst case you can reboot to get back to square one.
 

• If you are wired, unplug the RJ-45 network cable connector.    Result: complete loss of connectivity to internet and local lan (including networked printers).

 
Reverse by plugging in the cable. Assuming you are using DHCP you might have to issue a command from a command prompt: “ipconfig /renew” (without quotes) to quickly regain access.
 

• If wired or wireless, from a command prompt, type “ipconfig /release” (without quotes).     Result: complete loss of connectivity to the internet and local lan (including networked printers)

 
Reverse by issuing a command from a command prompt: “ipconfig /renew” (without quotes), assuming you are using DHCP.
 
For this next one you need to know the ip address of your router/gateway and it will only remove internet access (unless you set up multiple subnets).  You will still be able to access a networked printer or other systems on the lan that are configured to allow sharing/access.
 
From a command prompt issue the command “ipconfig” noting the listed Default Gateway.  You will need it later.
 

• From an elevated command prompt (run as administrator), issue the command “route delete 0.0.0.0 mask 0.0.0.0” (without quotes)     Result: loss of internet access

 
Reverse from an elevated command prompt (run as administrator) by issuing the command “route add 0.0.0.0 mask 0.0.0.0 192.168.?.?” (without quotes) and use your default gateway that you noted earlier in place of the 192.168.?.?
 
I used to be able to do this with a 3rd party firewall but since I don't use it any longer, I made standard shortcuts on my desktop with these commands.  I can simply right click on them and run as administrator to use them.
 
Best of luck,
Dave

if he's on DHCP then ipconfig/release should be already enough assuming i got the reason behind the loosing the internet thing.

If your computer skills are a bit above average you could go the next step and just disable the network card from DOS or a batch file. It's all up to you wether you want to see that information or not. Don't want to scare you with tech wizzardry so i'm leaving it up to you. If you want that info PM me or reply here and state that you want to know how.