MacBook Pro 15" 17" Models A1151 A1212 A1229 and A1261, are well know with GPU issues, turn on no display. internal or external. No water damage? Did you try different ram? no beeps ? original owner? , you can try to flux GPU on the logic board with heat gun, lots methods, some bake the logic board at 90 c. ect. Not permanent fix , I fixed my friend macbook pro 15" with clear flux 6 months ago still working.

three beebs indicates a problem with RAM. http://support.apple.com/kb/HT2538 Take it out, clean the contacts and replace it properly making certain that it is seated firmly. If still no success, you may need to get new ram, I found out my 4gb ddr3 ram was the issue did not work any laptop( no boot) or macbook same issue 3 beeps.

The same problem happen to me on my macbook pro 15" I put some diamond cpu compound on CPU and GPU. After I reassembled turn on fans full speed, slow process. Reading forums thermal sensor cpu got damage i was worried, then someone advise check every screw, few of them were loose, . fix the problem for me. Now Temp does not go over 60c viewing 1080p video =) with 4000 rpm fan speed. Check wireless cables, on my case one was loosed.