Problem with Finder and Menu Fonts (uppercase A)

Question

Hello --
I'm having a problem with fonts. All the characters that appear under icons in the Finder or in the menu for any application appear as uppercase As with boxes around them. There appears to be one uppercase A for each character that should be there. If I click-pause-click to edit the filename in the Finder, the text appears normal during the duration of the change, and then reverts to uppercase A with a box around it again. All other operation of the computer is normal.
I was watching and downloading video files in iTunes when the problem appeared. When I pressed ESC to exit full-screen mode, the Finder said that my start-up disk was almost full, and I saw the font problem. Upon investigating, I discovered that my start-up disk was completely full (and the download had failed), so the first thing I did was move some video files to an external drive, which freed about 5 GB.
Since freeing the space, I've tried the following to fix it, in this order:
1. booted from Tiger CD to run Repair Disk from Disk Utility
2. rebooted from the boot hard drive to run Repair Disk Permissions from Disk Utility
3. run through Disk Warrior
4. created a test admin user and logged in as that user
5. removed font cache files using terminal
6. booted in safe mode, logged in as myself, and then rebooted normally
None of these actions has had any effect. The computer is still operating normally, except for the characters that don't display correctly.
I'm running 10.4.6 on a Titanium Powerbook 500 MHz with 512MB RAM. A few months ago, I replaced the internal hard drive with an 80GB Seagate.
Tibook 500   Mac OS X (10.4.6)  

Answer 1

Hi again, zoobieboots —
I appreciate your initiating a new thread. Your post here helps to make the situation much clearer than in bmewolf's thread — particularly in terms of what you've already tried. Thanks again.
A few initial thoughts —
    (a) As I was trying to suggest previously, you're apparently operating (after moving some files to an external drive) with ~6-10% (?) free disk space. Particularly given that you were working with large video files when this appeared, File fragmentation would be expected. While I haven't heard of this particular symptom resulting from fragmentation, that would be a concern to me — particularly since this immediately preceded the problematic behavior.
I've read some good reports about iDefrag, but haven't used it myself. A demo version is apparently available for HDs < 100GB. But you'd presumably need to free significantly more space first (you haven't actually said whether 5GB or ?? is the total available now). Having never experienced severe fragmentation, I don't fully understand its consequences — but another participant may be able to explain this.
    <b>(b) You don't mention trying to troubleshoot potentially corrupt or incompatible fonts (or font caches), also as outlined in the other thread. As I suggested there, The X Lab's "undoing Font Book" FAQ is a useful resource in this.
    (c) Although I agree it may be an unsatisfying "solution," an Archive & Install did work for bmewolf in the case that you've indicated matches yours closely.
I hope one of these suggestions is helpful. Please post back to discuss your progress.
Regards,
Dean