Method 1: The system isn't always completely DEAD. Sometimes, it simply won't start because of faulty or damaged system files, malware attacks, software problems, or missing DLLs. In such instances, the BIOS utility built into the system can be used to retrieve data. Follow the instructions below:

• Connect the dead system to a USB drive (made with the Windows Media Creation Tool).
• Turn on your computer, press the F12 BOOT key to access the boot menu, and select the USB installation media.
• You will then be taken to the Automatic Repair setup.
• It will say that the Automatic Repair failed to repair your computer, so select Advanced options.
• Click Troubleshoot->Advanced options-> Command Prompt.
• The window for the Command Prompt appears. Hit Enter after typing notepad.exe.
• Select File > Open from the File menu in Notepad.
• Select This PC from the drop-down menu, then go to the files and folders you want to recover.
• To access them, change the file type to the 'ALL FILES' from txt.
• Select the external disc from the Send to the menu by right-clicking on the chosen file.

If the data is stored on the c: drive, however, this procedure may fail. With the NEW Windows installation, the c: disc will be formatted permanently.

Method 2:

If your system won't start and you're worried about the loss of data, you can use the dead PC's hard disc as an external drive and follow the steps below:

• Remove the hard disc from the affected computer and attach it to a functional computer. To utilise it as a hard drive, use a hard drive connector such as a SATA to USB converter or an external Hard Drive Enclosure. Connect the hard drive to the PC using an appropriate connector if the PC supports PATA/IDE 3.0.
• Open Disk Management  by right-clicking (or long-pressing) the Start button and selecting disk management.
• Assign a drive letter to the hard disc if the system recognises it but shows it as RAW.

Method 3:

When your system fails to boot and you attempt to repair it, you run the risk of losing vital data. To avoid data loss, use reliable data recovery software to recover your important system files, photographs, videos, and documents. These programs provide a bootable recovery disc feature that enables you to recover data from crashed, corrupted, formatted or non-bootable computers.