I would try resetting the NVRAM and PRAM and see if that helps. Here's a link for how to accomplish this:
You don't mention how old this iMac is. If it's extremely old, it's possible the internal battery is dead, which could also cause this problem.
I hope this helps.
thanks for the tip rkaufmann87, I only have guest access though.
Mike Osborn, I bought the computer back in 2010, it's still has Apple Care warranty I just cant call them until tomorrow when business opens.. i was hoping i could fix this today.
I've tried the PRAM reset to no avail.
I've tried going to users and groups (under system pref) and unlocking it so I can make changes... it's not even recognising my administrator name or password.
I've checked that all my files are still on the hard drive and they are, i just cant find a way into my account to access them.
I've tried searching this problem but can't find anyone who has had something similar happen, it's so frustrating!
can you open terminal as the guest user?
What happens if you type:
if you can access your account in terminal like that, then you should be able to open system preferences with your admin userid by doing something like:
open /Applications/System\ Preferences.app
and then take a look at the login settings for your user account.
I'm really out of ideas on this one.
If you don't want to wait until Monday (really? AppleCare has limited hours? Didn't know that!) then the only other thing I can think of would work....but it would take time.
Assuming you've got a current Time Machine backup, you could always boot to the Snow Leopard DVD, erase the hard drive, and restore it from your Time Machine backup. But....it seems kind of extreme to me, so there may be better suggestions posted by other users here.