My Dimension 5150 is just over a year old (thus out of warranty) and it suddenly started rebooting every 5 minutes or so.

 

I opened the case and reseated the power supply connections but now it won’t come up at all.

 

Checking other posts on the forum I’m leaning towards the power supply. When I plug in the power cord now, the system attempts to power up, the motherboard LED lights solid, and the front panel hard drive indicator blinks along with 1, 3 & 4 (which doesn’t match any diagnostic code -http://support.dell.com/support/edocs/systems/dim5150/en/sm/tshoot1.htm#wp1114195). It then dies for 3-4 seconds and repeats this until I unplug it.

 

Is there any way to narrow down if this is Power Supply or Motherboard?

 

In other posts it looks like the Power Supply wasn’t the issue but I hate to just buy a new Motherboard if it’s a (less expensive) power issue. I hate to throw parts (money) at the problem till it goes away. These days it may be cheaper to just buy a new computer.