I did a few things:
This I got from someone on the net, can't remember where.
Control Panel --> Power Options --> Select Power Plan
> Change Plan Settings (I kept it at 'Balanced')
>> Change Advance Power Settings
>>> (expand to) PCI Express
>>>> (expand to) Link State Power Management
>>>>> (select) OFF
Bumped my video card fan speed from 38% to 65%
Installed the newest Windows 7
drivers for nVidia cards
So far so good although it didn't happen very often for her, the weekend should tell.