Should I install the full retail version of Windows 8.1 on my Windows 7 OEM PC?

When I upgraded to Windows 8 using an upgrade disc, I felt that Windows 8 was not quite performing to my expectations. Since I upgraded my power supply, I seemed to have multiple issues with it and reinstalled Windows 7. Then it seemed as if Windows 7 was not running as fast and stable as it had before. As of late, the PC would sometimes not detect an internet connection when booting. This has not been a problem when I tried reinstalling Windows 8.1. I had weird issues, like not being able to sign on to my Microsoft account and OneDrive sync issues. It seems as if my current Windows license does not like hardware upgrades, even if it's a power supply. My original power supply died, so now there's no point in trying to upgrade to Windows 8 without issues. Would a clean install of Windows 8.1 full version on my Windows 7-preinstalled PC be a cure-all solution for my recent issues given the changes in hardware? Would Windows 8.1 run much faster as a standalone OS rather than an upgrade?
 
Do I have to search for any drivers for the motherboard, CPU, or anything like that? I know about Windows automatically searching for video drivers and manually getting peripheral drivers. There are some bloatware programs, such as HP MediaSmart and Microsoft Office Starter 2010, which are worth keeping, but others, such as ATI Catalyst drivers, which are rather annoying.
 
I called Microsoft Support and they told me that since I'm running my original Windows 7 OEM license on a hard drive other than the original hard drive, then there will be performance issues. With that being said, I'm prepared to buy Windows 8.1 retail. Windows is not installed on my old hard drive, which is still plugged in as the E drive. Should I delete the D drive (recovery partition) first, do a clean install of Windows 8.1 on the C drive (formatting that partition during the process), and leave the E drive alone and still plugged in with my games and stuff still on it? Or should I format the E drive as well?
 
Windows 8.1 retail installation went smoothly and Windows 7 has been retired. Now I can finally run Windows with no bloated background processes and have the full performance and capabilities of it. Even sleep mode works fine with no BSODs. I have yet to install games on it, but I'm sure that games will run better, albeit a few Windows compatibility issues. OneDrive is synching my files and settings between PC and tablet. Now all random Windows performance issues should be no more.