Dell G5000 gaming desktop motherboard 0M6C7G have an LED/ARGB light connector/port.

You could opt for a SATA powered controller such as this or this.

@DellG5000  This PC runs the Alienware Command Center (AWCC) which, amongst other things: 

"... enables you to create, assign, and share game-specific lighting maps to enhance the gaming experience. It also enables you to create your own individual lighting effects and apply them to the computer or attached peripherals. AWCC embeds Peripheral Controls to ensure a unified experience and the ability to link these settings to your computer or game...".

There is a the daughter LED board controlling the LEDs. So would those LEDs are visible inside the case if you added a clear side panel? If you're careful, you might boot the PC with the case slightly open to see if they're visible inside...

Otherwise, is there any way to connect to that LED board or to tap into the cable going to the existing LEDs?

I read about what you've said about AWCC somewhere before but didn't consider it. I slightly opened the case and booted my PC but only the geforce logo on the side of my RTX 3060ti lit up in white light and there we're no other lights or LEDs on etc. There must be a way to tap into the daughterboard to control the new LEDs from the existing LED on the front bezel i guess. More research needed methinks.

Thanks for your input

I was thinking along the lines of this https://www.amazon.co.uk/Lights-Remote-Compatible-GoogleAssistant-Solution/dp/B08YDGH63M/ref=sr_1_18_sspa?crid=2BQB4PHMWUEE&dchild=1&keywords=pc+case+led+strip&qid=1622476356&sprefix=Pc+case+led+str%2Caps%2C204&sr=8-18-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyMDdVSlZQUEwxWkoyJmVuY3J5cHRlZElkPUEwMjkzNDI1MU1ZRVhFWjBPS1dJTSZlbmNyeXB0ZWRBZElkPUEwODE1MTk0MlIxQk1TVkpPRlJOWCZ3aWRnZXROYW1lPXNwX210ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU%3D

It has a remote control where you can change the colour by pressing the buttons on the remote control.

@DellG5000  When you looked inside, were the PC's case LEDs visible from outside, but not visible inside?

Don't know about that LED you linked. How will you connect its PSU to the LED strip inside the case? Are you going to have to drill a hole somewhere?

Or just go with something like @JOcean linked with a SATA connector...

That appears to be more for external use such as an entire room. Would it even fit inside a PC case? And after looking at the sites I mentioned, one of them would require a controller (the PC board with multiple connections). The second would connect directly to any LED strip. 

EDIT: After a little more Google work have a look at this page. It has some great ideas and some of them do have a remote control. Just make sure you choose one that does not require a motherboard connection.

@DellG5000  - If you look at the image of the LED daughter card in the G5 5000 Service Manual, it has multiple headers of various shapes. Only one appears to be used for the exterior LEDs.

I don't see any documentation for that card, so maybe you can look at it closely to see if any of those headers are clearly marked for what they are. Maybe that can help you find a compatible LED strip to mount inside the case. Or if the card has a label with the manufacturer's info, maybe you can contact them to ask questions...

Thank you for researching it. I'll take a look at the daughterboard to see if any of the connectors are labelled and/or contact the manufacturer.

Thank you for your continued help. Much appreciated.

I've looked at the daughterboard and it looks like there are only two slots and the front bezel LED is plugged into it but the front bezel was not plugged in on the kb photo in the link which made it look like it had more connections on the daughterboard than it possibly has. I cannot see that there are other connectors on the daughterboard but they are obscured by other panels in the case, I can't see the connectors apart from the two which the front LED is plugged into and I can't figure out how to remove the daughterboard from the motherboard even by looking at the daughterboard KB you've linked for me. I did see three connectors (SATA 1, SATA 2 & SATA 3) close to the daughterboard but I think that it quite possibly be part of the motherboard, not the daughterboard but i'm not sure. The connectors on the motherboard are well labelled as to what the connections are but I'm unable to see what the other connections are on the daughterboard. Sorry to be a pain.

Glad to be helping...

The LED daughter card image in the service manual shows 3 headers (two 6-pin, one 10-pin), which I marked with red boxes, and it looks like something is printed along the edge near each one.

Are you saying your card doesn't have them? The service manual only mentions one cable connection for the front LEDs.  I guess it's possible they used a different daughter board in your PC...

The three SATA headers you see are on the motherboard and would be data connectors for three SATA (hard and optical) drives and can't be used for anything else.

Hi @RoHe Thanks for your reply :),

On closer inspection there are the headers which you describe on the daughterboard. I have ordered an LED SATA kit from amazon. Here's the link to the LED kit: https://www.amazon.co.uk/DreamColor-Computer-Magnetic-Adhesive-Spectrum/dp/B07NXW4K5T/ref=sr_1_1?dchild=1&keywords=dreamcolor+sata&qid=1622888891&sr=8-1

Thank you, I did wonder if those three sata ports on the mobo were for supplying power but then I thought the sata power might be supplied from the PSU (found this out whilst researching). Glad i'm not going to try plugging in the LED into the sata data ports on the mobo but I doubt it'd fit as the 5v connector in the LED kit appears much bigger in photos than the ports on the mobo. Guess they're different sizes for a reason to prevent accidental incorrect connections, which is a good thing!

I've now just got to find out where the sata power cable connector is (that's if my pc has a spare sata power cable). It must be nestled somewhere behind the PSU but I can't see it yet! Got my ESD field service kit coming today so I'll try and delve a little deeper to find the sata power cable source. 

Ps I'm enjoying doing the research and i'm hoping that i'll soon come to a resolution and can't wait to have the LEDs sorted.

Good job!

Thank you.