Bought a new laptop, installed Win 10, and then installed Kubuntu

It was running Win 10 fine for a few days.

I installed Kubuntu to have a dual-boot laptop

but the problem is

After installing Kubuntu 20 LTS

the GRUB 2 show when I turn my laptop on

but it does not show Windows

And when I enter Kubuntu, Kubuntu does not recognize Windows partitions