Logonui.exe system error shell32.dll mising HELP!

I downloaded a icon pack installer yesterday and it told me that i needed a restart for the results to take place... when i restarted my computer it came to the log on screen where i would usually enter my password but the screen was black all that was visible was the cusor, a turn off button at the bottom right and a windows 7 ultimate logo at the bottom.
There's a screen that comes up saying,

LogonUI.exe - System error
The program cant start because SHELL32.dll is missing from your computer.
Try reinstating the program to fix this problem

Can anybody please tell me how to fix this!!? :huh:

The following steps may help.

• Use http://www.sevenforums.com/tutorials/666-advanced-boot-options.html to choose Repair Your Computer.
  
  
• Use the http://www.sevenforums.com/tutorials/668-system-recovery-options.html to choose System Restore.
  
  
• Use OPTION TWO of http://www.sevenforums.com/tutorials/700-system-restore.html to restore your system to before the problems began.

I have the same problem...
When I turn on my PC, the error is:

LogonUI.exe - System error
The program cant start because SHELL32.dll is missing from your computer.
Try reinstating the program to fix this problem

I can't access to the program, what should I do in case of that problem?
Do I need to back up my files and format my computer?that's the only what I'm thinking
or
there's some easy solution to fix it.because I can't access to the SAFE MODE, just to the BIOS set up that I don't know what will I do there...
Please tell me how can I retrieve the SHELL32.dll...

Do the following steps:

• Read carefully through http://www.sevenforums.com/tutorials/2083-system-repair-disc-create.html...
• Use the System Repair Disc to access the System Recovery Options...
• Use the http://www.sevenforums.com/tutorials/668-system-recovery-options.html to choose System Restore...
• Follow OPTION TWO of http://www.sevenforums.com/tutorials/700-system-restore.html and pay close attention to the NOTE: in OPTION ONE step 8.

If that does not resolve it: http://www.sevenforums.com/tutorials/219533-troubleshooting-windows-7-failure-boot.html


And if you still need help after all that, please start your own thread.