SQL Server 2008 - How would I create a dynamic query for finding relationships and references to the primary key?

Question

Since I'm new and I've never shared, and yet there are a few useful scripts that I need on a daily basis, I thought I should.

As a new DBA, some data fix DML operations and simple business logical analyses are much faster when I have a template with which I can check the constraints in a very large database with hundreds of tables. Pinal Dave's script (source posted in the answer below) was a great help as I started, but since then I expanded on it a bit to include the possibility to search for referenced ID's in related tables as well.

I hope this proves useful to some of you guys!