I’ve been having the same problems as almost everyone here with opengl, and I just figured out how to fix it. I run winxp with sp1 and I kept getting the subsystem error. Here’s what I did:
If any of you have matlab installed on your computer, there’s a program running in the background called matlabserver. It seems to really mess with opengl. Go to Run and type in “msconfig”. Go to the services tab and uncheck anything relating to matlab. Don’t worry, matlab still works fine if you do. Now restart and opengl should work 
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At least, this was how I fixed my computer. Hope this helps someone.