I tried creating a separate login on my computer with no distractions, and tried to get my work done there. This reduced my productivity because it increased the cost of switching back from procrastinating to working.

A technical problem that is easily solvable. My approach has been to use VMWare. All the productive tools are installed on the base OS. Procrastination tools are installed on a virtual machine. Starting the procrastination box takes about 20 seconds (and more importantly a significant active decision) but closing it to revert to 'productive mode' takes no time at all.