Have a double check in your bios that Raid mode is selected.
And both of the drives used in your raid 0 array are still each tagged or selected as raid on the connected sata ports or controler set.
If it all seems ok, and you have an optical drive and a windows os install disk for windows 7,8, or 10.
Boot from the Cd or dvd drive and run the windows setup, choosing the repair tools option on the main page where it asks you where or what drive to install windows to LGenius.
You may have to set the cd or dvd rom drive in the bios boot order list to number 1.
Or if you have a usb flash drive with a boot able windows setup and install image on it.
Set Usb devices to be the first boot device.
It should repair the errors on the raid array.
If it is just a data corruption of the booting partition of the raid 0 array.
If you do not have one.
Then you need to create one on a DVD R disk, or a usb flash drive on another laptop or system you have and then use that on the laptop with the broken raid 0 array.
That is of course if one of the drives of the raid 0 array just has a corrupted boot partition causing the problem.
If the drive has physically failed then your out of luck.
But you can always check to see if it is just bad contacts between the drive and the internal sata docking of the laptop.
Remove each drive and then slide each back in to the laptop.
As sometimes it can just be because the contacts of the connector of the laptop and the finger board of each drive just need re seating.
may of moved a bit if the laptop was transported, or experienced change in temperatures if moved from one location or environment to another. due to heat and expansion and contraction on cooling.
Hope it helps give all of the suggestions a try.