passwords

afternoon all.
I recently had to change my Apple password while I was away, due to locking it up. on my return i switched on my Mac of course the system sync'd with my apple account and flagged up a wrong password. However it will not accept my new password, or for that will not do anything when i click any of the buttons, either the sing out, ok, forgotten password. it just hangs. although i can input fine. I've tried rebooting and quitting and restarting. but not having much luck. my thought now is to try and reset my password back to the original on my iPhone. but this if it lets me use an old one, doesn't really solve the problem.
any thoughts appreciated.
Ps I've looked, but can't find... can you access your personal posts on this forum from a link anywhere?
many thanks Trevtt

In order to reset the password on your Mac you'll need your original recovery install DVD to boot with. Boot from the DVD, accept the language, then go to the top menu "Utilities". From there you can reset the password.

your havin a laugh arnt ya? I can do it on my phone, but have to go through a setup procedure to do it on my mac :s
ok, but I've upgraded from my snow leopard OS, to lion via a download. does this mean i can still use the dvd?
Have inserted the dvd and it presents the following install mac os, dvd or cd sharing setup, optional installs, instructions...?
or i can just reboot, and hope it starts the dvd which is what ill do now. just wanted to get this down before all my windows close...

Probably a silly question. How do you boot from the os DVD?

Restart and hold down the C key when you hear the startup chime

Alternatively, restart and hold down the option key until both the hard drive and the DVD are visible on screen. The hard drive will be selected by default, but push the right arrow to select the DVD and then press enter.

Be prepared to wait quite some little time for it to boot from DVD ... takes a LONG time compared to booting from hard drive. Be patient.

Not being funny guys, but my problem relates to iTunes/ icloud conectivity. All I've succeeded in doing now is creating a password that needs to be entered at startup. As well as a guest account. Which I don't want at all. Plus it's still not accepting the new password. So now it's totally screwed up.