power connection

I am having this unusual behavior in my PC. When I start My PC, after it not being connected to Power supply for more than 1 or more hours, it doesn't boot! -The start sound is there (normal boot sound) But only red LED is lit. The green LED doesnt lights. -Monitor screen is like not connected...

I bought iball 621v (no discussion on the ups model/brand please...) It has three 3 pin plugs right behind it. My doubt is , if I use a power stripe/spike guard (just to extend the cable length) and connect all my devices to only one of these 3 plugs , if there any issue with that ? in...