You said you deleted only MS fonts at first. Since you now only left System fonts, run Font Finagler, it could still be a font in the font caches somewhere. How many fonts are listed in System/Library/Fonts?
Can you launch anything MS in Safe Boot mode to see if it is a third party item or font.
Open the Terminal (located in Applications/Utilities) Type: sudo update_prebinding -root / -force and press Return. When prompted for a password, enter your admin password, you won't be able to see characters being typed, and press Return again. The process is complete when the Terminal returns to a normal prompt. Type exit and press Return.