Breadboard - that isolates any kind of case problem.
Breadboard with just motherboard, CPU & HSF, case speaker, and PSU.
You do have a case speaker installed, right? If not, you really, really need one. If you case or motherboard didn't come with a system speaker you can buy one here: http://www.cwc-group.com/casp.html
You can turn on the PC by momentarily shorting the two pins that the case power switch goes to.
You should hear a series of long, single beeps indicating memory problems.
Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU.
The problem with OCZ PSU's is that, depending on the model, they range from "pretty good" downward to two steps above junk. That's why I do not recommend OCZ PSU's. (I'm old. I never can remember which are the good ones.)
So, the best bet is to replace the PSU with a known good one of similar power capacity. Brand new, out of the box, untested does not count as a known good PSU.
Next best thing is to get (or borrow) a digital multimeter and check the PSU.
Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.
You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.
This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.
Yes yes and yes. I'm not one of these young kids who think they've done it by reading about it.
I had done all of that prior to finding the advice you refer to on Tom's Hardware
It is a brand new out of the box PSU. I have checked it with a DMM unloaded and loaded. Power on (grey) goes to 5V then the whole thing resets itself. Exactly as it did with the old 430W PSU so I've blown my money on that one.
I have done exactly what you suggest here almost to the letter. I have a speaker from an old PC and verified it is ok by plugging it into my running PC first.
The only sound it makes on this i5 is 2 "pops". I initially thought it was a relay dropping in and out. I've looked at the Gigabyte site for the award bios post beeps and thought it could have been the cmos so I removed the battery for a few minutes.
I've also reset the bios to factory.
I have just never been in a position where I have built a PC and not have it work so I wanted advice on what to try first given I've outlayed the money for a reasonable kit and the shop may baulk at a refund because I am not a "professional" which by definition means work in a PC shop.
I think I'll go with the mb first because the chance of it being the CPU is less likely, unless of course I zapped it during install so that will be my second point of call.