Default settings after startup!!! Why???

[macfanforlife]

Ok, so I'm running 10.4.11, on a 12" powerbook g4 aluminum 1.5gh. Never had this issue before, until this morning.
If I do a restart, my safari, firefox, dock and probably more are reset to defaults?
Very annoying, all preferences are lost etc, firefox is removed from the dock, dock icons rearranged etc.
Unfortunately I have been running filevault for years without knowing of the issues it causes. I tried to turn it off yesterday, with no luck, (I get the message saying I need to have 4000gb free or similar) need to hook up my external harddrive and get all this junk off here (only 9GB free at the moment), then do a clean install I guess.
Only problem is I am on a course for a month, staying at a Holiday Inn and left my HD at home. Also reboot disks at home.
Ran disk utility/repair permissions for the first time yesterday.
Also had to run keychain repair today to try get rid of an annoying Safari keychain error message. That didn't work.
Any tips will be much appreciated!

Thanks!

Steve