TextEdit problems: causes spinning ball/freezes, can't make it default app

Question

I'm having some serious problems with, of all things, TextEdit. On an iMac running 10.4.11 with TextEdit v. 1.4 (the standard version for Tiger), I've been having the following two major issues:
1. About once per day, or at least once every two days, for absolutely no perceivable reason, while typing in TextEdit, I get the "spinning beach ball"; the same pattern happens every time: I wait about 6 minutes for the beach ball to stop spinning, then I try to "save" my open document; this causes another six-minute spin/wait, after which it saves. Then I try to "Quit" Textedit, and after another six-minute spin, it finally quits. Then, any successive action on my part -- clicking an application icon in the dock, or doing command-option-escape to force quit things, or basically anything at all, causes the spinning ball to return, and this time it will not go away. I've waited as long as two hours, and it just keeps spinning. Command-option-escape does nothing -- no response. Nor does command-period, or anything I could think of. The only way out of the freeze is to press the power button and turn off the computer. Terrible!
This ONLY happens when I am working in TextEdit -- no other application causes the problem. And it only happens when I have an unsaved TextEdit document topmost on the screen. It has happened at least 30 times now, consistently, so it's not a one-time glitch. It has even happened when TextEdit was the ONLY application running -- so it couldn't be another application causing the problem. I had thought that "Classic" was causing the problem, because I often have Classic running to use a legacy OS9 application, but even when I restarted the computer and did not ever launch Classic, I still got the TextEdit-freeze problem.
2. None of my TextEdit documents have TextEdit as their default launch application. Yes, I know about single-clicking the file, pressing "command-I" and in the Info box changing the "Open With" application to "TextEdit," and also then clicking on "change all" so that all similar files are opened with the same application. When I attempt this, it apparently makes the change, but in fact nothing happens: even after making the change, double-clicking the files does not launch TextEdit. In fact, it launches nothing at all, because when I check command-I again, the launch application has reverted to either "None", or to something mysterious called "ams1108.html", which not only is not an application, but it doesn't even exist on my computer (I searched for it).
HOWEVER, if TextEdit is already running, then when I double-click on any of my text documents, they will then open in TextEdit. But if TextEdit is not currently running, they won't open in it.
This applies to any file that has a visible or hidden "txt" or "rtf" or other normal TextEdit-compatible extension. Basically, any text file.
What is going on? I thought TextEdit was the most stable, most reliable application in all of Apple-dom. And I've been using it for years and years, but this problem has only recently started in the past couple months. I have no memory of making any changes to my computer that could have precipitated the change. Also: are these two problems related to each other?
I really don't know what to do. Any suggestions for fixing this problem would be appreciated. (And no, I don't have the original 10.4 install disks, so I can't re-install TextEdit, unless it can be downloaded somewhere). Thanks.

Answer 1

OK, Carolyn, I wrote down all my prefs (glad I did), trashed the prefs file, restarted, relaunched TextEdit, reset all my preferences to my liking (which had reverted to default settings), quit TextEdit. Then I tried double-clicking some text files -- and the same problem (#2 above) persists. None of my TextEdit or text files have TextEdit as the default launch application -- they're still all either "None" or "ams1108.html". And, as before, if I try to change it to "TextEdit" in the file's info box, then click on "change all," it does not work: not only does it not change all the text files to be TextEdit, but clicking "change all" will cause the file in question to revert to "None" or "ams1108.html". However, if I only change the default app for that one file to TextEdit, and don't click "change all," then it will stick -- for now at least. (Though I wouldn't be surprised if after a restart they all changed back to "None.")
The short assessment is: trashing the prefs did NOT fix problem #2 above. It may or may not have fixed problem #1 -- hard to tell immediately, since the only way to find out is the use TextEdit for two days.
So, setting aside problem #1 for now: any suggestions for fixing problem #2 (default app can't be changed to TextEdit by clicking "change all")? I have thousands and thousands of TextEdit files I use, so changing them all manually one-by-one isn't feasible. Thanks.