Hi Micjax,
The configuration you describe should at the very least display POST/BIOS.
1. You mention no beeps. Any signs of life from the motherboard (CPU Fan spins)?
2. You mention an AT power supply. Check the power supply plugs are the correct way round http://www.playtool.com/pages/psuconnectors/connectors.html#oldpc.
You can also see the correct orientation in this picture.
3. I'm not sure if the Rage XL Video card is original equipment (others may be able to confirm), but I can confirm that most PCI or AGP cards should work for the BIOS.
If you have the little speaker connected to the motherboard, then I'd suggest removing everything apart from the processor and one RAM stick (if there is more than one, remove one, and test with one and then the other). If this produces no beeps then remove all the RAM and test.
With no RAM and a functional motherboard and processor you should get a beep code (one long beeeeeep, if I remember correctly) meaning "No DRAM Detected / DRAM Fault"
Regards
John