Its a shame we cant have stores dedicated to helping people build, and upgrade, their own PC.
Just imagine, if you could just order it, get what you need, delivered to the store (with no worries about damage/theft), have someone nearby to help and answer questions, and get exactly what you need, for a good price. And for the less techy, have a tech there to show you whats being done, and to make sure you know how to care for your new machine. And best of all, when upgrading, they could offer to buy back any usable tech (for a reasonable price) which could make upgrades even cheaper, while providing low cost "refurbished" parts for even lower cost low end building, as well as better recycling of parts that cant be re-used. And no worries about having to get the right setup for safe upgrades, as they would have all the techy stuff, ready to help you upgrade!
The store could be VERY small, and run almost entirely out of storage, as the majority of what would be needed for the day, could be kept ready and waiting for the scheduled customers!