From MSDN samples primestep2. This error is particularly disappointing. It is using Visual C++ Express Beta 2. It worked on the Beta 1 but that has now expired. I got the example from MSDN Oct 2004 and I had to convert the .sln file to the recent version. I am particularly interested in using assembler language as can be included in C++ and I have learnt how to get output file in assembler but I do not know how to use this assembler file (feed it back into Visual C++).I also know how to copy and paste assembler from the window in Visual C++ but have not been successful in using it. Can someone please tell me how to make this sample work? Edward Jones. e.mjones@btopenworld.com