macbook pro A1286 15" keyboard, trackpad and usb not working

Hi, I have a 2010 macbook pro (A1286) 15" and tried to update to snow leopard using a friends disc since i dont have mine. We tried to get it to boot from disc but it would just get stuck on the startup apple logo screen with the disc still going. then, we left it, went out and came back but it was still stuck on the same screen. When we turned it back on the keybaord, mouse and usb ports werent working. We changed the trackpad and keyboard but it still didnt fix the problem. Then, one day, it miraculously started working again and was fine for about a month but now i have the same issue. No keyboard (cant even use usb mouse or keyboard), trackpad or usb. The usb still gives power to my external harddrive but doesnt read it. Any thoughts on what the problem might be? I took it to a store but they said they couldnt fix it and take it to apple. Thought i should try this forum before i go to the effort of booking in with them.
I have searched through the forums and there are plenty of posts about keyboards and trackpads not working but not all 3 (keyboard, trackpad and USB).

Could we have overheated something when we left it on for so long? Why would it suddenly start working again and then stop? So many questions......

All I can do is turn it off and on. When I turn the computer on it looks fine and takes me to my home page but the mouse doesn't move.

I am having this problem as well on my 2009 17" MBP. It was working perfectly fine the other day until last night when I got home from work I started it up and the trackpad and keyboard were unresponsive. Plugging in my wireless mouse or my external keyboard did nothing but like you said it would give power to my external hd.

I havent recently done any major changes or updates just typical browsing and using itunes. I tried rebooting several times without luck. After searching a bunch of forums and posts I also tried rebooting in safe mode by holding shift, as well as trying holding Option, Command, P and R while starting up with the same result. Login screen looks normal just the trackpad and keyboard or usb wont work