computer won't re-login

[thporter2000]

I have linux/ubuntu 11.04 and firefox browser not sure of the version, when I leave the computer it dosen't(always) login from the screen saver sometimes and I have to disconect the power and reboot, I have ipod, ebook and memory stick, I'm wondering will it stop me using these(refuse to read them) not so far, can u help is there a fix for this?

[hal8000]

There is only 1 password on Ubuntu a user password, this is used even for root with sudo access.
You can create the root account and set a different password, so if youve done this make sure you enter user pasword and not root password.

You say "sometimes". Define sometimes. Does it work 4 times out of 5 or something else?
You can try pressing ctrl-alt-F1 to see if an alternate console is available, never disconnect power this can harm your hard drive, instead hold the power button for 5 to 10 seconds until it powers off.
Hope that helps.