how to bring my laptop to previous state if my windows crashes?

[vikyy17]

my laptop came with windows 8.1 pre installed and just yesterday my cousin messed up with the windows files in the c drive and it crashed. now my laptop isn't even booting the OS. i cannot even acesss "advanced settings" option for me to get to the system restore option, i have not created any system restore point though!please guide me to restore my laptop to the way it was i purchased it i mean to have a clean genuine windows installed

 

[algis0762]

Can you boot in "safe mode"? F8 after BIOS/UEFI finish just before Win start? If not; boot with your install disk and go to repair section (not sure Win.8)

 

[USAFRet]

my laptop came with windows 8.1 pre installed and just yesterday my cousin messed up with the windows files in the c drive and it crashed. now my laptop isn't even booting the OS. i cannot even acesss "advanced settings" option for me to get to the system restore option, i have not created any system restore point though!please guide me to restore my laptop to the way it was i purchased it i mean to have a clean genuine windows installed

There should be a Factory Restore function. Look in the user manual for how to invoke this.