Printer issues

Hello all,

Sorry I am new here and not really sure if it been covered.
I have 2 new notebooks, Windows 7 OS. I started with the free Avast and everything was working fine, wireless internet, wireless connection to the printer, etc. I upgraded the machines to Avast Internet Security and no more connection for my printer, its says its off line. I removed and reinstalled free version and it works, I could not find any settings to allow me to make it connect to me desktop to print.
Desktop runs XP SP3
Please help, dont want to think I wasted money and can not use the better program.

Dave