Problems with MSS DLL drivers for playing PC game "Half-Life 2"?

I wonder if anyone could advise me about MSS DLL files? I am not a great PC expert, but have some understanding of how a PC works....however, I have just installed the game "Half Life 2 " on our PC which has Windows XP operating system, and last year I downloaded the MSS DLL 32 driver from their website to (as far as I remember) the Windows System 32 and Windows System folders on the C drive.



However, when my son tried to play the game (which uses an online system called "Steam" which I managed to install OK), it came up with two error messages, the first of which said:



"The MSS DLL file is installed in the Windows or Windows System directory; it must be installed in the application directory." then



hl2 application error:

'The instruction at "0x241f94f7" referenced memory at "0x0e5ef41c". The memory could not be "read" .



Any suggestions? btw,It looks as if MSS 32.dll is already installed in the Apps directory, perhaps I need to overwrite it?



Many thanks.Problems with MSS DLL drivers for playing PC game "Half-Life 2"?
might be in the wrong place?