The best place to begin judging from these photos would be to take out all the cards to give them and the motherboard a good dusting down.
Some times just reseating hardware can fix boot issues, especially if the contacts are dirty or oxidised.
While the cards are out it's worth taking a closer look at everything to see if any capacitors have leaked.
If everything looks ok still, reseat the memory and only plug the the graphics card back in and see if you can get it to post.
No visible bios can be caused by a few things. Bad GPU, bad memory, dead motherboard, bad power supply, or sometimes just a rogue piece of hardware which isn't compatible with the rest of the setup.
I think we can rule out that last one if the machine was put into storage in a working condition.
Best of luck. W.
PS. The motherboard looks like a Chaintech 7VJL KT333 which sockets an AMD Athlon/Athlon XP/Duron CPU. A review from 2002 can be found here https://hothardware.com/reviews/chaintech-7vj … d-review?page=1