Intel Splash Screen But No Boot

3 yr old unit worked ok last night. Today it won’t boot. All I get is the Intel motherboard splash screen. Drives spin up. Drive activity led lights. No Beeps. No boot process at all – just the splash screen.
Running Intel D875PBZ board with SATA raid 0 (twin raptors), 1 GB ram dual channel mode 800 MHz, agp single video card 9600 pro, 480 watt ps with extra connector to mobo, creative audigy card
Assumptions:1. video ok, memory ok, drives ok mechanically, 2. problem likely in bios or processor – What do you think??? I really can’t afford to replace whole thing at this time…..