To purchase, "Online vs. Brick & Mortar"

I recently went to upgrade a few things on a pc that I bought only a few years ago, (actually less than 2 years ago). So, just trying to do research on my existing pc has become a nightmare. Even-though I have an account with a few venders it seems as if they are asking a little too much information, especially in this day and age of cyber theft. 

I could understand if it was over 5 years since I made purchase, or if I was making a large purchase such as a house, or a vehicle but I’m not. I’m buying a battery and another accessory to work with some of my software. This endless amount of research and for all of the problems that I’ve been running into with “re-establishing” my account that’s less than 3 years old, I’ll just go to the local Radio Shack, to get what I need, or go to whatever the other Brick & Mortar store has in stock.