(2010 Macbook on Sierra) White Screen of Death "Legacy Shim 2"
From what I understand, I think that this is a trackpad driver issue. Try booting up while holding the Command and R keys, and then re-installing macOS. 

If that doesn't fix it, then you may need to install a new trackpad. You can find instructions on how to do this here. As for buying a trackpad, you can probably find one on eBay here, like this one.