ntcom.exe and mdfcom.exe

I'm running a scan with AVG.

Every time the desktop loads it says that windows explorer has encountered a problem and needs to close. After I send the error report the desktop icons disappear. I also occasionally get DEP messages after the error report message. When I shut down the computer I get messages referring to ntcom and mdfcom.

After that a small window appears in the top left of the screen that says loading personalized settings for ntcom.exe the same thing then happens with windows explorer a second time and then another box appears in the top left of the screen for personalized settings for mdfcom.exe

I believe that ntcom.exe has been corrupted due to a trojan. However, I have no idea what ntcom.exe or mdfcom.exe are for.

I've run Ad-Aware and it detected a trojan. I then had it quarantined. That's when the messages and errors started.

AVG has detected trojans associated with both ntcom and mdfcom. Should I get rid of mdfcom and ntcom or are they necessary and need to be repaired?