AutoCAD Architecture 2010 stopped working at startup

I made an installation of ACA 2010 64-bit on Vista 64-bit and after after installation I could not start ACA. I tried to make a repair and still same problem.

It almost started ACA completely but then I got “AutoCAD Application has stopped working. A problem caused the program to stop working correctly. Windows will close the program and notify you if a solution is available.” I did not get any CER dialog after that. acad.exe just then silently crashed.

As I have Visual Studio 2008 I did also try the Debug option and after that I actually got a CER dialog. Other than that the only thing to do was Close program.

I tried the Process Monitor and identified that the last loaded ARX file was AcPEXCtl.arx so I renamed it and was able to launch ACA just fine.

Update. So much for this workaround. Today AutoCAD Architecture 2010 crashed again so it seem to not be related to this ARX file anyway.

Anyone knowing what AcPEXCtl.arx is and why this happens?

I noticed that if I got ACA running I could after that manually load AcPEXCtl.arx without any problem.

Update and my solution.

I tried with /nohardware switch and it didn’t work but when I also run it as administrator as well I got it running. After that I could start it as normal.