OK, when are you supposed to be getting the new PSU? Maybe tonight..
Please Run Memtest86+
Information
Please download from this site
http://www.memtest.org/ in the middle of the page are the Download links, you can download the ISO.zip or the Auto USB Flash Drive installer.zip
Extract the Zip file. If you chose the ISO image, burn it to a CD using Windows Disk Image Burner or any Image burner you mat have. If you downloaded the Auto USB installer, extract it, insert your USB 2.0 Flash Drive and take note of the drive letter. Run the installer, select the Flash Drive Letter, check the format box and press next. It will install memtest86+ to a flash drive. You can use either V4.20 or V5.01. Boot from your selected media. If you use V5.01 it will tell you to press certain buttons at the start, please press no buttons. The test will begin on it's own and continue to run until you stop it. It needs to run for 8 complete passes or until you receive an error. If you receive an error, stop the test. Even 1 error is a fail. Each pass tests a different part of the ram and each of the 10 tests in each pass tests something different. It takes a minimum of 8 passes to completely test the ram, more passes are better. It is quite a long test and will take several hours depending on how much ram you have. Due to the time length it is best to run overnight. If you have any questions, please do not hesitate to ask.
I want to make sure you are not having memory problems. It should not be crashing in Safe mode. Safe mode only loads enough drivers for Windows to run. Basically it loads no 3rd party drivers, only Windows drivers which will not crash unless you have corrupted system files or hardware problems. Without the 450 installed, I doubt you are pulling 125 W from your PSU. You have run tests on your hard drive and passed, That only leaves the ram or Motherboard unless the software was right about your PSU, which I doubt.
Have you ordered the PSU yet?