RDP won't work after disabling windows firewall service

I recently disabled the local windows firewall service on several 2008 servers.  I later found this isn't the best way to do this so I enabled the service again and then shut off the firewall via the control panel instead.  Now on about half of those machines RDP fails to work, normally just timing out.  I've made sure RDP is enabled and I'm using a domain admin account for access.  I've also checked the registry settings here to be sure its not disabled there:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\fDenyTSConnections (set to 0)

I'm sure this was caused by me disabling the firewall service but I don't understand why RDP fails even after its been turned back on.  Any assistance is much appreciated!

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Dan