When I try to set the cooperative level and test the program the a messagebox tells me that register ESP was not saved across a function call and that it is ussually due to a function of one calling convention being called by a function pointer of another. Needless to say WTF! if( FAILED ( lpdd7->SetCooperativeLevel( main_window_handle, DDSCL_FULLSCREEN | DDSCL_EXCLUSIVE | DDSCL_ALLOWREBOOT ) ) ) { //whatever } help!!!!!!!!!!!

help me please..........

It should work... are you sure that that line is what''s causing the problem?

Yea, that line looks OK.
You might consider remming out chunks
of your code until the error disappears.
Rem out large chunks at first, then slowly
re-introduce the functions until the error
re-occurs. Then that will be your problem
function.
Looks like the stack pointer register.
Most likely a memory error of some kind.
Check on how you pointers are declared,
and how variables are passed to the functions.