Logging onto Windows 7 machines

When I try to logon to Windows 7 machines with a known administrator enabled username and password, I get logon failures. This doesn’t happen when logging onto XP machines, any help?
All machines are in WORKGROUP

We have had no issues with our Win7 machines. If the account your logged in with is already a admin you don’t have to type a username and password into Comodo Admin Mode. You can also try logging in with the machinename\username or username@machinename (seeing how your not on a domain) and password if any. Also, in the CESM you can set a master password for the CIS and push to that client.