Lagging BIOS and Boot - ASRock AB350M Pro4

[gazzaknightmedia]

Specs:
Ryzen 5 1600x
ASRock AB350M PRO4
GTX 1070
Corsair Vengeance 16gb (2x8) DDR4 2400
3x kingston 240gb SSD
1x WD blue 750gb HDD
Corsair TX550M PSU

Booting is taking upwards of 5 minutes in some cases. ASRock screen for about 2 minutes then a flashing white underscore on black screen for another few minutes.
When I enter the BIOS it is EXTREMELY laggy and pretty much unusable, with the mouse jolting around all over the place, as well as the timer in the bottom right hand corner going up in multiple second intervals.
Things tried:
Flashed to latest version of BIOS (5.50)
Booting with no drives connected
Booting with no USB devices connected
Disconnecting the MOBO battery for 5 minutes and reconnecting
Bios Screenshot:
https://imgur.com/a/kcBnfcj

When the PC boots it runs absolutely fine, so currently I am just putting it to sleep but it is very frustrating knowing I can't turn it off or use the BIOS. The build is only a few weeks old, but I have only had this issue recently. When I first built it there were no issues and it was booting very quickly with the BIOS working fine.
Any advice appreciated!

 

[norcalsc]

do you do a clean and fresh install of win10? or did you use an OS from an old system? if yes to the second question I would back up any important data and do a clean install of win 10

 

[gazzaknightmedia]

do you do a clean and fresh install of win10? or did you use an OS from an old system? if yes to the second question I would back up any important data and do a clean install of win 10

Hi, thank you for the suggestion.
The install was a clean install but I believe there were some windows files on one of the drives that created a windows.old folder.
The issue still persists even with no drives connected and therefore no operating system technically on the system. Could Windows still potentially be the issue in this case?