I had some problems because of missing fonts for a certain document. That caused pdflatex to fail (no PDF generated at all).
However TeXnicCenter did not recognize this error at all and tried to open the non-existing PDF file.
The relevant lines from the (stdout) log are:
!pdfTeX error: pdflatex (file md-chr7y): Font md-chr7y at 572 not found
==> Fatal error occurred, no output PDF file produced!
This lines should be marked with the error red cross and build process should stop.
Additionally the returned code of pdflatex.exe was 1 - indicating an error. IMHO TeXnicCenter should check the process response code and stop if it is not 0.
BTW: For generating this log I had to execute pdflatex manually on command-line because I did not find a way to copy the relevant lines from the TeXnicCenter log window. How can I copy some/all lines from the log window to clipboard or a file?