Turn off the DEP function of Windows XP SP3

Some friends do not like the DEP (Data Execution Prevention) function of Windows XP SP3, because some software is always interfered when running, want to completely turn off DEP, as follows.
We need to do something about the C:\\boot.ini file.
First, change its read-only property, right-click on the file and select "Attributes" to cancel the "read-only" attribute.
Then use Notepad to edit boot.ini and find the entry starting with multi(0)disk(0). At the end of that line is /noexecute, which is the sign that DEP is in effect. You can change /noexecute to /execute and finally restart the machine. This closes the DEP.