Quest for restoring a ps3... to be completed

[Watevah]

Hey guys, even though I've lurked here for quite a bit and picked up lots of useful information it doesn't mean I'm now a ps3 expert and I have come for your suggestions. So here is a story of my PS3:

I bought a ps3 on eBay, the seller said it was working and displayed video but had no HDD and BD in it. I decided to have a go at repairing one of those things and, oh boy, how wrong I was.
A blu-ray drive was bought as well and I was planning on remarrying it to the mobo, I had a spare laptop HDD lying around so I didn't have to buy that.
I was hoping to remarry the drive by getting to the service mode using factoryservicemode-tool-v0-2 (can't post a link, but you can google that)
After acquiring all the bits I started "fixing" the damn thing. At first I couldn't install the CFW, but eventually I got it on the console, it was Waninkoko v2 3.55, I had to make the install to ignore missing components so there wasn't a problem with a missing drive.
Being close to success was only a moment of bliss as the console stopped broadcasting video signal.... I've sent the board for reflow and it was nicely fixed.
This is where things became ugly... The ps3 started shutting down with no reason emitting 3 beeps and was not booting up, every time I pressed the power button it gave 3 beeps and shut down instantly.
Now I start getting a feeling that this piece of plastic is mocking me, sometimes it WILL TURN ON and let me use the XMB for some 2 minutes, after that comes the usual, 3 beeps and dead.
I have tried 2 different PSUs and 2 hard drives, all giving the same result.

Anyone has ideas as to why the hell after wasting 110 pounds and tons of effort this thing isn't working?

Much appreciated.

[Watevah]

Thanks guys, I threw it out of the window, it's all fixed now!