SSD Not Detected

I am trying to upgrade a old Dell Laptop for a friend with a SSD.
I have a WD Green 240 SSD.
When I physically install the drive (there is a hard drive caddy that pulls out of the side of the laptop), the new SSD does not show up in the Bios as NO Physical Primary Drive is detected.

I dont know what else I am supposed to do at this point??

TIA Bart

When your new SSD is connected properly with the laptop open your diskmanagement = diskmgt.msc.
The new disk will be shown without letter. Click right and choose to change or apply a letter
(sorry, this is all NL) Otherwise someone may tell you in English

Thank you

to me it seems like although the hard drive is mounted in a caddy when i physically insert this back into the laptop the new SSD is not actually clicking in and connecting.

I put the new SSD in an external hard drive and I can see it , I have initialised it too.

The BIOS doesnt see the device either

I have booted up from a Bootable USB and looked at the drives using AOMEI Partition Assistant and it doesnt see the drive.

there was an odd Remove Before Installing yellow sticker on top of the drive which seemed to do nothing and I removed but its not doen anything

This is really quite odd

Check that the "access protocol" in BIOS is set to AHCI, not to IDE, ATA, etc.

Thanks I checked this earlier after it was mentioned in a Google Search and it was set correctly :-(

Additional info:
https://www.dell.com/community/Stora...958732#M319107

Check the physical alignment.

The ssd is not connecting inside the hdd caddy.If possible,can you disconnect the caddy leads and connect them to the ssd directly?
I'm not familiar with the Dell laptop and it's build.