Question : the windows firewall has become disabled

windows live onecare left my windows firewall disabled after I uninstalled onecare.  How can I reenable the windows firewall.  I am not planning on reinstalling one care at this time.  
The settings are visable, in the off position, greyed out with no user access

Answer : the windows firewall has become disabled

From this Previously Answered Question at Experts-Exchange:

http://www.experts-exchange.com/Security/Win_Security/Q_22055347.html
Windows Firewall options are greyed out

a comment from expert (and Page Editor) rpggamergirl:

These keys are probably created by the virus:

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\DomainProfile]
"EnableFirewall"=dword:00000000

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\StandardProfile]
"EnableFirewall"=dword:00000000


values set to zero --> disables it and it greys out the buttons so it can not be changed
values set to 1      --> enables it and greys out the buttons so that it can not be changed
The value has to be removed so that the firewall is not set either way and he has control over it.



OR:
Also check here:
http://windowsxp.mvps.org/resetfwpol.htm