The browser processes are working as they should. You can't just shut down one process. That's not how it works. Each process serves a purpose. The browser isn't the issue. As far as finding the offending program (if that is indeed the issue), when you have the processes up in the device manager, click on the top where it says "memory". That will sort processes by memory usage. I can't be sure that's the issue, but if you want to post a screenshot of your processes sorted by memory usage, we can look at it and see if that's the issue. You may have a bunch of bloatware running, especially if it's a prebuilt computer. It really is hard to know without physically looking at it. But maybe a look at the background processes can give us a clue.
As you can see in my screenshot, I'm right at 4gb of ram usage, and I just had 5 chrome tabs open, dropbox, AVG, and mostly just normal startup programs. So it really doesn't take much to hit that threshold.