@jimdeppner 

 

If Windows 10 takes more than 24 hours to install even after replacing the hard drive with an SSD, the original disk was probably not the only problem.

 

Dell provides built-in preboot diagnostics for the Inspiron 3670, so run those before attempting another installation. At power-on, tap F12, choose Diagnostics, and run the full extended tests—not just the quick test. Record any error code and validation code. Dell specifically recommends its preboot diagnostics when troubleshooting slow performance and hardware-related problems.

 

Also try a different USB port, preferably a rear motherboard port rather than a front-panel port. Recreate the installer using Microsoft’s official Windows 10 ISO or Media Creation Tool and, ideally, test with a different USB flash drive. A bad USB stick or corrupted installer can make Setup appear to hang for hours.

 

Use Dell’s memory diagnostics first. If the diagnostics are inconclusive, run a bootable MemTest86 test for several passes. Do not assume the RAM is good merely because the computer reaches the Windows installer.

Inspect BIOS settings
Load BIOS defaults first, then check: SATA operation is set to AHCI, unless the existing installation specifically requires RAID.The SSD is detected correctly.
Boot mode is UEFI. The Windows USB is booted in UEFI mode.
Secure Boot is temporarily disabled only if the installer has trouble booting; it can normally be re-enabled afterward.

 

Do not repeatedly change RAID/AHCI modes after Windows has been installed, because that can make Windows unbootable. For a clean installation, AHCI is generally the simpler configuration unless you need Intel-specific RAID/Optane functionality.

 

Since the system remains slow after Windows 10 has been installed and the SSD has already been replaced, the hard drive alone is unlikely to be the cause. Please check Task Manager to see whether CPU, Memory, or Disk usage is abnormally high, then run the Dell F12 preboot diagnostics. Disconnect any secondary drives and USB devices, reseat or replace the SATA cable, test the RAM modules individually, and install the Inspiron 3670 chipset/storage/graphics drivers from Dell. If it is still slow with a known-good installer, SSD, SATA cable, and tested RAM, the motherboard or power supply may be failing, and further part purchases may not be economical.

 

If still under warranty, contact Dell Support by clicking the blue "Get Help Now" on rightside of page.

 

@Sharan G​ Thank you for your support! When I ran the diagnostics it gave me the following 2 errors about a hard drive.

Version: Build 4400.07 UEFI ROM

Error Code: 2000-0151

Validation Code: 103348

Hard drive 10 SIN 303PGA04PTKL, incorrect

status = D

Critical Warn Degraded Read only No space Avail

 Also,

Version: Build 4400.07 UEFI ROM

Error Code: 2000-0151

Validation Code: 103348

Hard drive 10 SIN 303PGA04PTKL, incorrect

status = D

8000000000000007

Could not send DST Short