I can type in programs, but if I type anything on the mac itself (login name/password, search mac help, etc.) some letters don't show up but they are registering as being there. Any message I get from Mac is missing letters and looks like gibberish.
I noticed it yesterday in Mail (Inbox is "ib") but it seems to be getting worse. Attaching a screen shot example.
Boot from Disc 1 (that came with your Mac; hold down the "C" key on startup with the disc in the drive, after the Mac restarts), and go through the install process. Your data will not be affected. When you get to the window where it asks you to select a destination, go to "Options..." and select, "Archive and Install." Do NOT select "Erase and Install" under any circumstances. Your OS is broken.
__________________ ACMT Mac mini (Mid 2011) 2.7 GHz i7, 8GB RAM, Crucial M4 256GB SSD + 500GB + 1TB FW800 OWC Mercury Elite Pro mini iPhone 4S • iPod nano 8GB • Sound System Audio Engine A2 • Display UltraSharp U2412M 24"
I had it off and on at least a dozen times. I installed something called onyx which some site said had a utility that could do something. Clicked on it, panicked because it started running something and I didn't know what it was doing since of course the message was all garbled, hit the power button and forced it off. When I turned it back on everything was normal except the system preferences which I fixed by deleting something called com.apple.preferencepanes.cache
I've never seen anything so bizarre. Every time I rebooted it got worse, then suddenly I reboot and it's all better.
Looks like maybe corrupt/damaged system fonts that sometimes loaded properly and sometimes not... damaged fonts can cause any number of nightmares like this (and more!)
The only time I had to do a "clean" reinstall was due to a corrupt font. Even knowing the responsible font, I had to boot from the install disk to remove the offender and that proved to be a temporary fix. Loooong time ago, since then I make sure I have a complete system back-up before installing new fonts, OS updates or anything else that could possibly corrupt the system.
Do NOT Touch this computer!!! Touching this computer WILL cause irreversible brain damage.