Are you running zonealarm free version on both machines? If so, be prepared you can't get the ICS working because the free version doesn't 100% support ICS.
You can install this on the host machine if they don't work.
If you just have zonealarm on the host machine then open up zonealarm's main page:
Click firewall > main > lower the internet zone security to medium > then click zone > add > ip range > in the pop up add ip range box, top ip address row, type 192.168.0.2, then type 192.168.0.20 in the bottom ip address row(you can put 192.168.0.2-192.168.0.254) > name of your workgroup in the description box > apply
Turn off the window firewall on the host machine with zonealarm on.