On Windows 2003/2008 Servers running anything over SSL (ie HTTPS) via applications like IIS, Terminal Services (SP1+) and ISA Server even if the application can set ‘Force 128bit encryption’ other weak ciphers are still availible on the server.
 To stop this:
1) Backup your registry or at least export the key HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSecurityProvidersSCHANNEL
2) Copy below into a text document and rename to .reg

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSecurityProvidersSCHANNELProtocolsPCT 1.0Client]
“Enabled”=dword:00000000
[HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSecurityProvidersSCHANNELProtocolsPCT 1.0Server]
“Enabled”=dword:00000000
[HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSecurityProvidersSCHANNELProtocolsSSL 2.0Client]
“Enabled”=dword:00000000
[HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSecurityProvidersSCHANNELProtocolsSSL 2.0Server]
“Enabled”=dword:00000000
[HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSecurityProvidersSCHANNELCiphers]
“Enabled”=dword:00000000
[HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSecurityProvidersSCHANNELCiphersDES 56/56]
“Enabled”=dword:00000000
[HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSecurityProvidersSCHANNELCiphersRC2 40/128]
“Enabled”=dword:00000000
[HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSecurityProvidersSCHANNELCiphersRC4 40/128]
“Enabled”=dword:00000000
[HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSecurityProvidersSCHANNELCiphersRC4 56/128]
“Enabled”=dword:00000000
 

3) Double click the .reg file to run and answer Yes to dialog
4) Confirm working ciphers.  A good site is http://www.serversniff.net/content.php?do=ssl 
 Have fun