Previously dual boot with Win10. Now boot missing. Help.

I did a dual boot with windows 10 and managed to use clover manager to switch between OSes.

After a while, I deleted the Hackintosh but held to clover manager to boot into Windows. I had to change the CMOS battery and thermal paste last week. After that, the laptop won't boot into Windows. The usual clover UI doesn't appear on boot. Instead greeted with "Operating system not found" message. And also I can't enter to Bios setup. I think it enters into Bios setup page but all I can see is a grey/black screen.

I verified with live Linux USB that my SSD is healthy and can access the drives.

Is there a way to fix the boot?

Laptop - Dell XPS L502X. Using modded A12 bios for Nvidia 525m graphics.