My MacBook Pro has an update available for Maverick I think it was

Question

My MacBook Pro had an update available for the Maverick and I did not hit the update because kept erroring out. I was updating other things and decided to hit it too and that time finally updated. Then right after the laptop looked for updates and did another one. It asked to install whatever the upstate on the OS or X was and then took 50 minutes to install it then more time to complete it. When computer finally came back on it asked for my apple ID for iCloud. I typed it in several times correct fly but it would not take it and finally chose forgot. It went to a new blank box with the asterisk wheel winding around and choice of continue highlighted below next to un highlighted back.  Now I am frozen here and can't do anything with laptop. Will not allow me to highlight and choose back. Can't get it to continue. Tried esc. Tried force close and tells me I must quit setup assistant first. Can't get top controls to show up. Finally got a second desktop background to come up and pushed F 3 and tried to use buttons below and above and will pull-up things like Safari but can't use it and can't pull up the set up assistant this way to choose quit either. So I am just stuck.  Help please, anyone. How do I get use of my laptop again??
I don't really know if it is maverick or what number OS it is. Just know had picture of mountain lion.

Answer 1

That sounds like you have installed Mavericks over the top of Mountain Lion?
Do you know what version of the OS was on the laptop before you started?
Do you have any backups from before the 'update', either a Time Machine disk or a full copy (a.k.a. bootable clone)?
Mavericks is not a simple update, despite Apple's constant nagging to 'update' to it. It's possible that the Mavericks installer has overwritten the old OS, but I suspect it may simply need you to create a user account with the setup assistant. It's a very good idea to make a full backup before applying any major OS upgrade.
I would reboot, fill out the details for setup assistant and when it is time to enter the user details enter a new account name (this will be your admin account). The assistant should then create a user account that you can login with to look at the contents of the Mac's disk.
Then you should open the /Users folder (Use 'Finder menu > Go > Go to folder…' to open /Users) & see if the old users home folders are still intact. You may also want to see if any third party Applications are still installed.
If the old data is intact, and the account isn't listed in 'System Preferences > Users & groups' it can be recreated, provided you make sure to use the same 'shortname' as the Users home folder.
If the data is gone, I'm afraid it's possible that it is lost, I can't see this being likley because the 10.9 installer will not delete user data without some stern warnings & advanced user interaction.
An alternative would be to connect this Mac to another Mac & look at the disk to see if the data is still there before you create the user acount. Do you have access to another Mac? You may be able to use Thunderbolt or Firewire to see this Mac's disk on another working Mac.
Target disk mode
http://support.apple.com/kb/HT1661