Imac g5 lost ALL preferences, Help?

My friends computer has been acting weird, which may shed light here. To my knowledge it's been a bit unstable, locked up a few times (she's a heavy multitasker) Had disfunctional mouse problems with multiple mouses(maybe it's her holographic mouse pad), had to have the OS recoverd/repaired once before, lost an occasional filemaker or word document. Luckily things are backed up so no real damage has ever struck. Here's what's unsettling.

All of the system and program preferences are gone! Everything was fine last friday when the system was shut down. Today on start up it's reverted to default. The screen saver's gone.. the email signiture gone..it's just gone. Applecare supposed the obvious.. a deleted system file. But it's not in the trash..nor would it have been removed, moved, or renamed. They were unable to help thus far. Could it be a virus, trojan?(we have Norton), could it be bad sectors that the Mac HD diagnostic couldnt' find? What do you think?

edit: yes we have wifi, and it's encrypted.. with wpa. I have checked the log and havent' seen any activity besides our computers

 

hard to say what it is for certain, but it looks like an hardware failure somewhere - HD as you said, maybe mobo, CPU or memory. And since the computer has been unstable as you said it might be some other hardware related problem... try using memtest OS X or Apple utility to test the memory; while both CPU and memory controller might trigger errors, it may indicate if that whats been happening or not.

 

Yes. I think you're right.. something else just came to light(big lebowski moment) sometimes the keyboard fails to work..as it just did a moment ago for her. Are there any other diagnostic programs you'd recommend??.. I will search also. This is getting fishy

 

As far as settings being "lost", hardware error is not a likely cause.

One thing that often causes this is that the user changes the name of their "House" (ie., their home directory) and since everything works fine just forget about it. Until the next time they start up, when OS X thinks "hmm, there's no home directory for this user" and creates a default one.

Have a look in Macintosh HD (under /Users/) and see if you see the old home directory. If you do, just rename the current one to something else, then rename the old one (the one with the "new" name) to the old name and log out/log in again.

If that isn't the issue, losing her settings sounds quite strange. Try running Disk Utility from the install disc (a couple of screens into the installer program you can choose it from the Utilities menu) and check disk permissions and the disk itself (verify/repair disk permissions and verify/repair disk). If it finds errors that it can't fix, you might have to reinstall.

Though if you have backups I'd recommend an erase & install if the problem persists after this anyway. If you still have issues after an erase & install you know that it's a hardware issue, so it's a good diagnostic tool (if one that you want to wait with using until you run out of options, certainly).

Try some of this and let us know what happens

 

Update: I had her download the mac utility that does a diagnostic.. Not sure of the exact name. Nothing came up. Then she ran one pass of rember, again.. all ok. I think we'll let it run a few more passes tonight after we leave the office. If things persist, we'll move onto Memtest. Unfortunately I'm also the only tech support here ( 2 person office ) so I might be left to do that after a 9-10 hour day as it is. Yay!

Now the strange thing about the lost preferences( the strange gets stranger) is the home folder is still visable and only a portion of the preferences are missing as it turns out. I'm not entirely sure what is still there or if she's just confused, but I'll have to look at it later. If that's true, I have no idea how that happened (maybe it's a computer gremlin). I will definitely try the renaming procedure you mentioned if I see another home folder. Unfortunately a mirrored back-up was never done, only critical files. Thanks for the help fellas. I'll definitely let you know when we fix it, and what it was..

Update:11:38 - so I saw the users folder as you specified.. and there's only 1 home folder, appropriately named. I'll try the verifying/repairing disk permissions next

 

If only some things are missing, see what verifying/repairing disk permissions does for you. You can do that from Disk Utility in the system without having to boot up to the install disc.

 

Well, the permissions were checked but needed no repair. So this scooby doo mystery continues.. I haven't had any time to even look at her computer though. So I don't know what the real deal is. Maybe it's Old Man Smithers in the gorrila suit costume. Hoping I'll have a few moments this afternoon -jimy