black screen on windows 7 after boot

Black screen on windows 7 after : windows is starting logo.

Well i have a laptop of cousin  with this problem so i decide fix by my self:
1- scan whole hard drive for some virus using your best antivirus for this scan and found 19 virus in registers , so all was removed for my antivirus. : )
2- Use of  ccleaner for eliminate any bad register and cookies
3- use of cmd in msdos, use this command : sfc /scannow     (wait for finish its work)
4- After step before in same msdos windows type: chkdsk /f /r   and wait for finish , after finish you will be able to see a comment press " Y "   without quotes and press press enter , after that restart your computer.
You will see something scanning wait after everything is finish then you have done , this error will gone out , hope you can fix it, if not try a new fresh installation of widows 7