Windows 7: Password box not working

When I come to the password screen, I type in my password and it freezes. Does anyone have a solution

Have you tried booting into Safe Mode to see if the same thing happens?

If you can get into Safe Mode like Devux said, open Command Prompt as administrator and type:
chkdsk /f
Should fix any errors that is causing the computer to freeze.
Or you can do Startup Repair using your Windows 7 installation disk (if you have one).

Can you log in when you boot into safe mode?

If yes, then while there, run SFC /SCANNOW from a command prompt:

In other words, run CMD.EXE and then type sfc /scannow and hit the enter key.

If it shows now integrity violations, ggod, but if not, then shutdown your computer and boot up into safe mode again and once again run sfc /scannow.

If you can not log on in safe mode, then let us know.

I can't

Learn how to reply so that you can be better served......

You can't what ?
To whom your reply was addressed ?

If you want to reply to one particular replier, go to that person's post and click Quote, then compose your reply. ( just like what I did ).

If your reply was for all the repliers, then go to each one and click Multi, one at a time, then compose your reply.

I can't boot into safe mode

How are you trying to boot into safe mode?

Safe Mode

Which method are you following? Method 1 is the most simplest

Here are 2 " step by step " instructions .......

1. How to boot to Safe Mode :
Turn computer off > turn it back on > immediately and repeatedly tap F8 key until you see a black and white screen. That is your safe mode screen. > use the up/down arrow keys and select Safe Mode with Command Prompt > can you login without computer freezes ?
If yes, you can logon in safe mode, then continue to #2.....

2. How to run system file check :
Click Start button > in the search box, type cmd > look at top left, do you see cmd.exe ? If yes, right click at it > click Run As Administrator > at the flashing prompt > copy/paste this command line.......
sfc /scannow > press Enter key > it will take some time > sit back and wait. Do not turn off the computer > when finish, it will tell you one of the followings ( I am paraphrasing )......
No integrety violation.
OR,
Found corrupt files but unable to repair them.

Post back after the file check is finished.