macbook reboot issues

i own a 3 year old Macbook, i think it's running OS 10 something or maybe OS9. i recently had to "hard" shut down (turned it off via the power button instead of doing it properly). now upon reboot, after i enter my password, it acts like it it about to reboot, BUT after approx 2-3 seconds it brings me right back to the password login prompt. i have done this about 30 times to no availi am the only one who uses it, it is NOT a password or login ID issue. I'm currently deployed to Afghanistan so taking it to a pro is kinda out of the question. i hope somebody can help

there's an eight and a half hour time difference from Kabul Afghanistan to the east coast so i presume everybosy is still waking up. hopefully by this time tomorrow somebody will have some advice for me.

OS 9 has been gone for 10 years.

Is it logging you out, or just asking for your Username and Password.

If its just asking for Username and Password it may be a problem with your Keychain, go to Utilities > Keychain Access, from the Keychain Access menu select Keychain First Aid.