My Dell Dimension desktop 9150 was running very

Hi,
the constant Green, states that the motherboard is getting Power.
The red/yellow would possibly suggest, that the ethernet port has a fault or possible corruption.
Solution:- remove the Power Lead from the Computer Case.
Remove side panel. take out any ethernet-Cable from the rear.
Locate the CMOS battery, round silver Battery on The motherboard.
For 10 seconds, this should reset The bios, to it,s original Default Settings. Replace Battery, side Panel. And power Lead.
You could also try This. Boot with Hard-drive power Cable Disconnected ( this will Eliminate HD Fault ) same for CD/DVD drive et,c.

Mike @ Compurepair.