pc game problem

first off i don't have a lot of knowledge of technical stuff. i have windows xp. i downloaded return to castle wolfenstein: enemy territory (full install) here's the link if anyone needs to look at it http://www.download.com/Return-to-Castle-Wolfenstein-Enemy-Territory-full-install-/3000-7565_4-10243511.html?tag=lst-0-1
after i installed it i tried to open it. it goes to a black screen then goes back and this box pops up that says GLW_StartOpenGL () could not load open GL subsystem at the top and says this inside the box-
...created window@0,0 (800x600)
Initializing OpenGL driver
...getting DC: succeeded
...GLW_ChoosePFD( 16, 16, 0 )
...35 PFDs found
...GLW_ChoosePFD failed
...GLW_ChoosePFD( 16, 16, 0 )
...35 PFDs found
...GLW_ChoosePFD failed
...failed to find an appropriate PIXELFORMAT
...restoring display settings
...WARNING: could not set the given mode (3)
...shutting down QGL
...unloading OpenGL DLL
...assuming '3dfxvgl' is a standalone driver
...initializing QGL
...WARNING: missing Glide installation, assuming no 3Dfx available
...shutting down QGL
----- CL_Shutdown -----
RE_Shutdown( 1 )
-----------------------
GLW_StartOpenGL() - could not load OpenGL subsystem

can anyone help me out here? any help appreciated. thanks!