Check BIOS First:

Enter BIOS (Del or F2 at startup). Check if drive appears. If not visible in BIOS, the issue is physical.

Use Disk Management:

Press Win+X > Disk Management. Drive may appear but need initialization. Right-click > Initialize Disk if needed.

Assign Drive Letter:

Drive visible in Disk Management but not Explorer? Right-click > Change Drive Letter. Assign an available letter.

Update SATA Driver:

Device Manager > Storage controllers. Update driver. Outdated driver may not recognize newer drives.

Check Cables:

SATA data and power cables may be loose. Try different cables and ports. Common issue after moving computer.

BIOS Settings:

Ensure SATA controller is enabled. Try AHCI vs IDE mode. Check motherboard documentation for options.

Conclusion:

If BIOS doesn't see the drive, it's a cable or drive failure. If BIOS sees it but Windows doesn't, it's a software issue.