Laptop- no power light but batt charges

So, I just picked up this non-working laptop to mess with. Dell D620, perfect physical cond. Charged battery no problem, however, no power light, no boot, fan, bios... nada.

What I have tried:

Replaced RAM with known working RAM trying one slot at a time.

Tried cold reset. (No cord, no battery, no cmos battery, hold power button 1 minute, rest a few minutes, replace battery, cord). No go.

Removed HD, RAM, DVD.. reset, rest, trid start w/out hd and dvd. Result- still no power.

I would swap cpu, but don't have an extra to try... any other ideas out there that I ave not tried?

Not too big of a deal, I only paid $25, but would like to get it going if possible. This was sold to somebody else through ebay as a reconditioned laptop, very clean in and out, but arrived in this condition.