I ran a search for this, but the answers I saw were referring to something altogether different than what I'm asking for. So let me clarify: I'm not asking how to change key-combo shortcuts. I'm asking--how do you actually change what your computer thinks you did when you press a given key?
An example of what I mean (and the reason I'm asking). I'm a Chrome user, and I use Windows alongside Ubuntu. I own a Lenovo Thinkpad T61p--it came with my scholarship package, and I would have shopped for a nice computer if I could have. The T61p has two buttons above the left and right arrow keys that relate to browser commands to go back and forth one page. This is extremely frustrating for me, as I use the arrow keys, and a single accidental keystroke will catch me going back a page, losing temporary data, and yelling at my stupid keyboard. At the same time, I'm the type of person who keeps way too many tabs open. Chrome doesn't let me refigure keyboard shortcuts, and the only way it allows you to switch between tabs are ctrl+tab and ctrl+shift+tab, and ctrl+page up/down.
I was using Notepad++, and they had finally found the solution to both problems! The page back and forth keys functioned as tab back and forth keys. I went through quite some effort to learn how to change the keybindings in Windows. The page back and page forward keys are now the page up and page down keys, respectively, and if I hit control, they let me switch tabs easily, and rather pleasantly. And if I hit the keys by accident, no harm, no foul.
Alas, I'm in Ubuntu now, and I need to go through the process again. And while I couldn't just find the answer online, like I did for Windows, I know Ubuntu has nice, supportive communities like this one, where, hopefully, somebody can tell me how to do either what I did in Windows, or directly make it so that my computer changes tabs when I hit those buttons (removing the ctrl button from the tab-changing command).