Hi Siddhish ManiPL,
I am Dave, I will help you with this.
On another working PC, you will need to create a bootable Windows 11 USB with the Media Creation Tool from the link below on a blank 8GB USB flash drive, then boot your Dell laptop from that USB, delete all partitions on your drive and then install Windows 11 from the USB.
Click this link:
https://www.microsoft.com/en-us/software-downlo...
to download the Media Creation Tool.
Then, Boot your PC from the Installation Media you just created (change Boot Order in your BIOS) to begin installing Windows 11
During the installation process skip the steps which ask for a product key and select the option 'I am Reinstalling Windows 11 on this PC', and activation will not be an issue.