>However, I read in help of function “SystemParametersInfo()”, I
>cannot find the parameters “41,42” that are used by you, I only
>see the form of parameter such as “SPI_GETACCESSTIMEOUT” in area of
>uiAction parameters. If you have free time, please show me about that.

Sorry about that: I thought I had mentioned it, but I see that I didn't. You can find those constants defined in the .h files that ship with Visual C++. At the bottom of the help file, it says Header: declared in Winuser.h -- that's the file you need to look in. If you don't have access to these help files, I'm not sure of the best way to find this information.