I hate to have to ask this but... I've seemed to accidentally hit a couple hot-keys and my Notepad is now showing text from Right-to-Left. What was a that hot-key combo and what can I do to reverse it back to Left-to-Right?
To toggle between right and left text :
strike the "menu" key (beside the space bar) - so you can see many options, with shortcuts underlined, like "Lecture de droite à gauche" in French
strike the "L" key - in french version of Notepad - or an other letter if you have english or other language version
As some may have been confused by the "specificity" of the Answer regarding the French version of Windows, and in keeping with the OP's actual question (and circumstance) the answer is as follows:
"Accidentally" 'hitting a couple of Hot Keys' causing the text to be Right Justified in Windows 7 Notepad was accomplished not by a "Hot Key" combination, (as some had suggested as CTRL-RShift or CTRL-Alt-R) but instead by using the Keyboard EQUIVALENT of [Right Click] & [Check]ing "Right to left Reading order".
This "accidental" keyboard sequence was [Menu Key] then [R].
To set things aright (using the keyboard, for the old-school typists), the sequence must repeated, i.e. [Menu Key] then [R].
To put out any "flames", let me reiterate; These steps are identical to the "Mouse-Centric" answer above, but in keeping with the OP's stated cause & problem.