Hi Alauddin,
This could be an issue with the physical hard drive that is installed on the computer.
I would suggest you to check if the drive is getting detected under Disk Management. Follow the methods:
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Method 1:
Follow the steps to check for the drive under Disk Management:
a)Press Windows and X key together and select Disk Management.
b)Check if you are able to find the drive in the list of drives.
Method 2:
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I would suggest you to refer to the manual provided by Asus to check for the drive priority under BIOS. Refer to the link to download the manual from Asus website:
http://www.asus.com/Notebooks_Ultrabooks/ASUS_ZENBOOK_UX32A/#support_Download_36
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You can refer to the steps from the manual to change the priority of the drive under BIOS and then boot to the computer.
Disclaimer: Modifying BIOS/ complementary metal oxide semiconductor (CMOS) settings incorrectly can cause serious problems that may prevent your computer from booting properly. Microsoft cannot guarantee that any problems resulting from the configuring of BIOS/CMOS settings can be solved. Modifications of the settings are at your own risk.
Please let us know about the status of this issue.