Windows 7 Install error

This could be a BIOS Problem, see https://www.dell.com/support/article/us/en/19/sln133635/how-to-fix-an-invalid-partition-table-error-on-a-system-with-a-ssd--solid-state-drive-?lang=en

Or you need ACHI enabled in the BIOS (by default Latitudes are shipped with 'RAID ON' set) to communicate with M.2 drives

If your Dell has internal HDD, disable it in BIOS and try again.

Please give the service tag of your Dell notebook.

There are some systems that just don't work with certain SSD drives.  Try a drive from a different manufacturer and see if things work better.  If the system previously worked with a hard drive, then the "burden of proof" is on the SSD that it's not the cause of the problem.

This is one of those rare situations where I would consider updating a BIOS.  Check the manufacturer's support site and see if there is a BIOS update that resolves issues with booting from SSD.  (If not, leave well enough alone.)

are you installing from an usb stick?
and is that an usb3 stick, or connected to an USB3 port? that often is the cause
windows 7 does not have drivers for USB3
so put the install on a DVD or USB2 stick

Load your BIOS default settings, save the changes and run new install. In partitioned step - delete all existing partitions on the drive and let Windows installer automatically partition the drive.

By updating BIOS you have loaded its defaults as I suggested.

Customer found his own solution.