These days I access non-Latin characters with Windows'
(Start»All Programs»Accessories»System Tools»Character Map)
You don't have to memorize any codes, you pick your font,
and you can tell in advance whether the character you want
exists in that font.
This works for single characters & short phrases. If I want to
type in Cyrillic, for example, I use another utility (Standard
since at least XP) that re-maps the keyboard to work like a
Russian PC: ???????? ???? ?????--????????????
You have GOT to try the free CompPad plugin (http://comppad.sourceforge.net/) for LibreOffice/OpenOffice.
It is not just an equation entry and typesetting system, but is also a full math computation environment, complete with units management, arrays and matrices, libraries, and plots, along the lines of MathCad.
Did I mention it is FREE?
If you haven't tried it yet, Open Office.org's Open Office Suite is great for formulas and equations which can be designed and inserted into documents, Power Point Presentations, Spreadsheets, Etc., all of which are included with the Open Office Suite which is Public Domain (note: free) software and in my humble opinion, much better than MSFT Office.
I do not believe the current versions have standalone capability. However, I do know that in old, old versions (something like Win95 and/or Office 2003) I used to keep a shortcut on my desktop and could/did run it outside of Office almost daily.
Note the following sentence from the link below, "It can be used as a standalone program or it can also be used from within applications that support OLE as an embedded object."