Welcome ABHI RISHI,
Since Windows 7 is an End of Service (EOS) product, Microsoft no longer provides mainstream support for it. However, you can still try the following workarounds.
To better understand your situation, could you first confirm:
- Is there still a Certificate of Authenticity (COA) sticker on the computer case or under the laptop battery that shows a Windows 7 product key?
- Was Windows 7 originally preinstalled by Dell, or was it installed later using a retail disc?
- What happens when you try to start the computer? Do you see any error messages?
In the meantime, please check for the product key sticker on the device. Many Dell computers that originally shipped with Windows 7 included the key on a COA label.
If the recovery partition is no longer working and the product key cannot be found, reinstalling the original Windows 7 installation may be difficult because Microsoft no longer provides Windows 7 installation media downloads.
Please provide the answers to the three questions above, and I'll suggest the next steps based on your specific Dell model and license type.