Sharing directories in Vista (Program Files)

Hello,

In the past when I was using Windows2000 I had the following setup:

Test_PC_1: Win2000, shared all files and directories
Test_PC_2: Win2000, shared all files and directories
Game_PC: Win2000, shared the temp and the Program Files directory
Work_PC: Win2000L, shared the temp directory

Now I upgraded my Game_PC to Vista (ultimate) with the same shares (All new installs)

Somehow the shares to the more sensitive erea's of Vista (Program Files) is not accessable anymore. I tried to share that directory and gave "Everyone" full permission but still I can't access it.

Is it possible to fully remove all security from Vista so everyone within the network can freely access the Game_PC?
I know this is a breach in security but I connect to the internet through a fifth computer (linux) which is acting like a firewall and has defencive software running.