well try this:
boot into safe mode with command prompt, see if you can log in, if you can, type this in:
explorer.exe
if you can't do that, then go to the startup repair WITHIN WINDOWS. do not use the disk. click the command prompt option and type the same as above.
(THE ABOVE OPTIONS SHOULD GIVE YOU A TASKBAR, IF THEY DO NOT, MOVE ON TO THE ALTERNATIVE METHOD) 
after that, if you have access to another computer, download viprerescue scanner from
here and open the file in your computer. It will ask where you want to extract it, extract it to a flashdrive you can connect to their computer. Connect the flash drive to their computer and run the scanner in her computer by clicking VipreRescueScanner.exe. while it scans, click the start button and type in the search bar "msconfig" (without the quotes, of course). click the startup tab and disable any programs that do not need to be started at bootup. If you see any strange programs, write the name and path of the program down.
ALTERNATIVE METHOD
Obtain access to another computer and download viprerescue scanner from here and open the file in your computer. It will ask where you want to extract it, extract it to a flashdrive you can connect to their computer.
Connect the flash drive to their computer and type in the drive letter of the flash drive, if you don't know follow these instructions:
Code:
Type C: (this should be their windows drive) look down the list and see if you see the Windows Folder, if it's there, it's not the correct drive (this is the same for the following instructions)
continue typing in the letters alphabetically in order (D: E: F:) until you come upon a drive that contains the file named VipreRescueScanner.exe.
in the command prompt, type this:
VipreRescueScanner.exe
a new cmd window should pop up scanning your computer. Then, while it's doing that, in the other cmd window type this:
msconfig (or msconfig.exe, i'm not too sure)
a window that contains a tab called startup should pop up, click that tab and disable any any programs that do not need to be started at bootup. If you see any strange programs, write the name and path of the program down.
