...Hi.....!!!
first rule of forum be polite and say hi.
+1 nbelote
If in windows you get this message, you got malware, download malware bytes and rogue killer.
If you start you computer and you get a black screen and you get that message:
1- your hard drive is dead and needs to be replaced
2- windows is corrupted - get your installation disk and boot from it.
Then try to repair windows. Go on google and type "repair windows X" + " operation system not found"
X is version of windows (xp, vista, 7 or 8) and you should find instruction on how to do it.