GRUB boot menu not shows win 10

Hii,
Today i download Parrot Security OS 4.8 Mate from the official website Architecture 64x.
Then i burned through a burning software… And proced to install… on restarting the pc i go to the boot menu previously selected UFID installation… and i process the steps finally i installed it in my 2nd drive HDD partition which has 200GB Space and going to successfull but one pop-up come and told me to install GURB boot menu and i selected yes because previously I’m using windows 10 latest version and it’s installed in my first drive SSD.
Then after successful completion of installation.
I’m used Parrot Security OS then turned off my pc. After sometime i restarted my pc then i try to open my old os but I’m not able to open my old os… from the boot menu because it not showing there… then i tried various steps as on internet but not able to boot in my previous os.

Please help me.
I’m very disappointed.
Please solve my problem.

Try booting Parrot then mounting your windows drive.

After this try running the following commands:

sudo os-prober

sudo update-grub

Then reboot. Let us know what happens.