Propriety Migration Yes Or No?

OK So here is the situation, I was asked by my niece if I could build a "Gaming PC" for her son! The answer was undeniably yes, but obviously budget was paramount. I was given a max of £250 ??????? yeah exactly! not possible I replied, with games evolving so quickly and the demands rising, that is no way to enter the PC gaming scene.

However! after breaking down the requirements into components, I could see that it was possible to obtain a reasonable CPU as long as it came in a propriety system such as Dell,HP,Lenovo etc.
What followed was research, leading to absolute horror stories purporting to the transfer of propriety boards, I can vouch for this, and advise anyone reading the thread to seriously think twice about attempting the transfer, This is the first build I ever made, that involved making my own wiring diagrams and a soldering iron.
No problem with the board size, it was MATX but the issues come with connecting everything up.

Let's put this into context, by buying a propriety Dell board I got a working system with 8Gb 1600 DDR3 Ram, 750Gb WD Blue HD, DVDRW Drive, Win 10 Pro, and an i5 3570 CPU, for £85

All it needs is a case with room for a decent GPU and I'm done, right? Wrong!

So issue 1
You need to check the wattage of the PCIe rails, the SFF and Mini have only 50w, whereas the MT type Dell cases carry the full 75w so the 6 pin or 8 pin GPU connectors are not necessarily adequate for GPU requirements, you must check!

Issue 2
None of the PWR/RST/HDD led/PWR Led etc will fit, in fact the entire header is propriety, in a different order, and at 2mm pitch
(This can be overcome, the Dell optiplex 7010 MT does not have a Reset switch anyway so there is no loss. Same with the LED's, they aren't needed.
Secret is, to remove the entire cable and switch from the original board, to utilize the header plug. The PWR on configuration relies on a live pin and 2 common, splitting the cable and soldering the case connectors to any combo of BLK Yellow or BLK Red, will do the trick to spark on the PSU

Issue3
The front panel header on the OKRC95 Board is, once again useless in this, as is uses a different configuration of pins, and they are at 2mm pitch, Trying to bypass any connection on the Dell board results in boot error notes, which are easily bypassed with F1 but are ultimately an unfinished conversion.
The USB3 front header can be connected with some force, due to the locater being a different configuration, but if you are wary about applying too much force, you can use a blade to remove the offending article from the male case connector to make it easier. It only goes in one way after all and it's just as easy to see what you've cut off as it is to see when it's there.
The USB2 can be put straight into the internal USB header on the board.
To avoid the system errors I cut the original plug down to pins 1-8, cut off all the connections 1-6 and shorted out 7/8 to remove the IO error on boot.
Unfortunately the FP HDAudio is also on the connector and can only be resolved by installing a sound card with an audio header, and bypassing the onboard standard.

Issue4
The PWR Switc fix, means that and AC input forces the unit into a 3 false start high fan speed frantic mode, however, changing the BIOS to return to previous state after AC input fixed this.

Issue5
Undoubtedly, the board will need latest BIOS updates, Sata controller updates, and HDD controller updates, which are all inherently dodgy

Issue6
The Sys Fan, which also carries a Dell alarm is a 5 pin straight header, it connects to a 90mm case fan in the Optiplex which is neither needed or easily transferable. However I bought a 5 pin to 4 pin connector, and a 4 pin PWS 120mm fan, which I mounted in the case to convince the Dell board that it was still there.

Issue7
The case fans,
Unfortunately there is no work around with this, there are no headers on the board to power the case fans, so if you want the fans to be functional, you will need a powered fan controller. Luckily I was disposing of an NZXT Shadow, which had a 6 way fan controller on the top, which I migrated to the new case, with some padded double sided tape.

Ultimately I don't recommend this, as a first time operation. I might undertake it again, but only with the knowledge I have gained from the first attempt.
I found it very difficult to find info on this, which is why I have taken the time to write this history,

To Summarize, I ended up with all case functions working except, Reset, and Led's
i5 3570
750Gb HDD
LiteOn 48x DVD/CD/RW
8gb 1600Mhz DDR3
ASUS GTX760
Cit 500W 80+ Bronze
ASUS Xonar DGX 5.1

Just benched at 68FPS on Unigine Valley full 1080p 4xAA and Low Tessellation 63Deg/Cel
Total cost £252

Case was Inwin Mana 136 - Have to say, very impressed, great quality, good space, tool less design was awesome, and £24.99 can't beat that!

If you're stuck on a similar stupid build, please don't hesitate to ask.