It could be a lot of things and you really did not tell us very much.
What version of AGP is the card and what version(s) do the motherboard support?
For that matter, what are the make and model of the motherboard and AGP card?
What was in the slot - or how did you get graphics support - before?
Did you remove old video drivers, if any, and install new ones?
Why make the change - any problems or issues before changing- if you changed?
Is your PSU strong enough for the card?
Are you sure the system was working fine 6 years ago before use discontinued and has anything changed on the system since then - other then the video card you will explain?
No, I can't even see the BIOS screen. Like there is no video output at all.
To answer your questions:
The AGP card is EVGA GeForce 6200 512MB GDDR2. AGP 8X
My motherboard is an AsRock P4i65G socket 478 motherboard
The hard drive is completely empty.
Originally, when I stopped using this system, I sold the AGP card that was in it before (Radeon 9250) to a friend. It was working fine before.
My PSU is 300 watts, which is the recommendation for the card, i believe
The system was working perfectly fine, the only things swapped out were the ram, video card and hard drive. I lost the old harddrive and sold the old PC3200 ddr ram that was in there before. Replaced them with new ddr PC3200 ram.