Normally the nvd3dum.dll error relates to graphics as you seem to be aware.
- I would suggest not using the most recent Nvidia drivers though.
The most recent Nvidia drivers have been causing a lot of issues. I can vouch for 310.90
working with my GTX560ti faultlessly. The 134.22 are also said to be good.
- Another option is a conflict with a service or starup programs, including your Anti-Virus
or various over-clocking/tweaking tools such as EVGA precision, and ASUS smart doctor
(if I have the correct name).
Try running in Clean Boot to troubleshoot these possibilities -
How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7
However -"I installed a new motherboard, did a reinstall of windows, to find that it won't let me activate it."
More an issue for the "Install, Upgrade and Activate" forum, but briefly -
Windows activation is linked to your motherboard. If your motherboard fails, and if the machine is recent enough, you may get someone on 'phone activation' that is sympathetic to your plight
who will give you a new activation key.
If not, you have to buy a new key (A new OEM from on line retailers is about the same price,
but don't buy from e-bay, or similar - Too many illegitimate Chinese copies ).
Windows will only fully function for a period of ??? before various functions start failing
(I believe updates is one), so not activating is not tenable in the long run.
.