Kernel-Power error ID 41 (task 63) causing total PC freeze.

Well then it just goes to prove that these things can be right out of field sometimes. But mate I would still check out that PSU after all the board is new and if the board was out of whack (old one) who knows if the problem may have been caused by some askew in the PSU - takes only a few minutes and what have you got to lose.
See my little ditty and use it to check the volts out
Using HW Info
You can test the volts on the PSU with HW Info HWiNFO, HWiNFO32/64 - Download < download the right bit version and close the right hand window select Sensors and scroll down to the power section where you will see what the volts are doing see my pic.
The original right hand window shows the machine running and is handy for that but for looking at the components in some detail close it and use the main left hand side panel
FOR OTHER COMPONENTS
Open each small square with + in it on the section the components are in and then click on the individual component/s (it will highlight in blue) - in the right hand side will appear all sorts of details including brands speeds and other essential info that particular device. See pic for example.
It is a good program to have on board so to speak for any of the component details.

Good to hear but hang on to that program HW Info it is very handy to have and is not space hungry:)

Now I know I am a fountain of confusion LOL!! but one last thing you might like is this if you haven't seen it already - I use it on all my machines (6) it really makes the machine more efficient if you don't mind losing a little of the "bling"
Optimize Windows 7

The meaning of Kernel Power 41 is simply The system has rebooted without cleanly shutting down first. That can be caused by any number of causes from a bad PSU to a short in the system, or anything in between. There is no single cause for that.

The point is that every BSOD is different. If there was a bug in Windows 7 ready boost, every Windows 7 would suffer the same fate. They all do not. Every computer with new hardware does not suffer from Kernel Power 41 errors nor does every computer with old hardware suffer from it. I am happy you tried that and it fixed your problem, but that will not fix everyone's problem.