This may be a stupid question, but, where is the render button in houdini? I am using houdini master non commercial.

On the Apprentice Learn CD's Video Tutorial section, there's a video on how to render. Just scroll all the down to the bottom.

If you don't that that it's available online at:
http://www.vislab.usyd.edu.au/sidefx/ [vislab.usyd.edu.au]

Specifically, the direct link is at:
http://www.vislab.usyd.edu.au/sidefx/cd2_5.5.208/pages/learn/video/index.html [vislab.usyd.edu.au]

1) Click on the type editor button( SOP, POP, ect).

2) Go to output (ROP)- rose grey in color.

3) On the right atop the parameter panel is a silver grey bar with “render”

4) Be sure to set up your desired render format and file save path, then click on the bar marked render. You should see the render window pop up in a second.

Good luck