A computer question (possible power failure on a Vaio)

I was doing a routine clean for a friend on her VAIO desktop (not the laptop!) when I opened it up and there was nothing other than a firehazard contained within. After about 30 minutes of compressed air, cleaning swabs, and a non-static dry cloth, I had pretty much gotten a lot of the decay/death out. I noticed that a fan was locked up so, having an extra, I ran out to get a soldering iron (leaving computer unattented and unplugged for about 20 minutes, possibly the problem?) I got back, soldered the fan on, closed the case up and hit the switch… nothing. No power.

I’m not extremely familiar with Vaios as I hear they’re in their own league. having just dealt with one, I see that.
I took a look at the fuse which seems fine and didn’t have a meter on me to test since I wasn’t expecting that. The backup battery is another possibility but this is an area that is somewhat gray to me.

What is the best route to take from here in order to test the power connections or other possible failures and their means to correct them? Is this generally a quick fix? I know this is GQ and it kills me to use this and possibly throw off the GQ nature but… What would you check and what would the process of trial and error be to investigate the possible failure?

Further, nothing starts, nothing shows any sign of remotely powering up.
And yes, it’s plugged in. definitely plugged in. :smack:

My only advice would be to get a decent digital multimeter and start checking things from the powercord onward.

The fix is often easy - it’s the diagnosis that can take a while.

Could you elaborate on this a little? Which fan? And when you say you soldered it on, what did you solder to where?

The fan located slightly above the power supply. A bit oddly placed in the VAIO. I took the preexisting three wires (RBB) and soldered the preexisting plug’s wires directly onto the fan.
I would assume if this were the problem, it would only affect the fan, not the entire power… correct me if im wrong.