PC boot only to bios

[ceazarbactad]

Motherboard-asus h270 plus
Gpu- msi gtx 1060
After accidently entered raid mode by my friend, pc only boots to bios and only i could see in boot priority is my HDD 1tb and would not able to see my ADATA SDD 120G.
please help

 

[Calvin7]

You need to reinstall the operating system.

 

[rgd1101]

undo the raid mode

 

[ceazarbactad]

How do i reinstall OS?