How to set a BPX at a certain instruction?
Such as POPAD,i want to make a breakpoint at POPAD in Si
and i dont know where it is.

Mitrix:

The code for POPAD has a certain form which can be used to search the code for the address, and then you set the breakpoint of the address you find. This issue is discussed in great detail in +SplAj's articles on CommView 3.1.156 and Awave Studio 7.3. You will find both articles and the page from his "discompress" page which contains the "signature bytes" to search for, down a few entries on this forum titled _SplAj Tuts. The fast way is to use this:

http://www.woodmann.net/forum/showthread.php?threadid=2355&pagenumber=1

Regards,