Nothing else connected.
Nothing else plugged in.
Short the 2 power switch pins on the mobo for a second.
If it won't power up your down to 3 parts.
Hello. I have an OLD PC, built in 2002ish, it was my main rig for many years, and was upgraded through the years until about 2010, when it was put into storage. Got it out today (6 years later) and won't power up. Replaced the mobo battery and still won't power. It has the red standby light on and when I hit the power button the cpu fan and case light flicker for a split second and then nothing. It is an Aopen Mobo. Any help? Thanks!