|When you boot to safe mode a number of thing are different.|
Many processes are not started in Safe mode. Many drivers are not loaded in Safe mode. Some hardware is not configured at all.
If you use Windows auto updater then you may have received an update or hardware driver that is causing the problems.
You can try to isolate by using selective startup. There are very few processes that need to run in order for Windows to boot. By unticking most processes and then adding them back in, one by one, you may be able to identify the issue.
Another thing you can do is look in Device manager while in Safemode and see if all hardware is working properly.
One other thing I can think of to try is to unplug the computer and reseat all cards, cables and RAM. RAM especially. Snap each stick in and out 4 or 5 times. If the problem persists run memtest86 from a boot disk to test the RAM.
The reason the RAM could be an issue in standard mode and not in safe mode is the memory ranges assigned to various programs and hardware may not be in use in safe mode.
What power supply did you install? Model number?