Hmm, that I wouldn't expect. When you pull the CMOS battery, it should reset the MEBx password to "admin", that's pretty standard (I've never seen a system where that was not true). What's especially interesting is that I was pretty sure ctrl-P was supported by that board, I've seen threads where people mentioned using ctrl-P to get into the MEBx on that board before.
For reference, the support page for that board is here:
http://www.intel.com/p/en_US/support/highlights/dsktpboards/dq45cb . I noticed there is a relatively new BIOS for the system, that might be the final resolution if the issue can't be resolved otherwise.
But first, on a DQ45CB, there should be an LED to indicate the current AMT state (if I'm interpreting the product guide right, it looks like it should be near the memory slots, but you might want to look in the product guide for yourself). Can youcheck whether that is lit or not when you power on the system? That should give an indication if AMT is actually enabled.
In the long run, it might be necessary to go to the official support page (here:
http://www.intel.com/support/feedback.htm?group=desktop ) We're focused more on development of software to work with the system here, as opposed to detailed system debugging, they'll be able to help with lower level questions.
