Xbox CPU thermal paste replacement

So I popped the heat sink off the CPU in my ‘chipped’ Xbox. I wasn’t able to get the heat sink off the device to the left of that, which might be the graphics card? I’m not sure. I gave it a pretty mighty tug and it didn’t come loose, so not sure what the deal is there. I cleaned the CPU and the heat sink (I damaged the heat sink a little, you can see the scratches).