Hello, mhk02,
When using your system to play games and making 3d models, go to Control Panel\All Control Panel Items\Windows Tools and launch System Configuration. Go to the Services Tab in there and click 'Hide all Microsoft Services', then click Disable All.
This essentially disables all non-essential seevices from running, then disconnect any peripheral devices you don't need while doing the task, 'Gaming or Modelling CGI'.
Then change the setting in 'Control Panel\All Control Panel Items\Power Options' to Power Saver plan, this should enabble you to complete the task at hand without the system crashing.
Other than these options, the only solution is to get the new PSU, unfortunately.
I hope this help's to solve your issue.
Orbitech.