Try replace cmos battery w a brand new cr2032, followed by clearing cmos settings via motherboard jumper.

1. Locate the CMOS reset jumper (CMCLR) on the system board.
   • NOTE: For more information on the location of the CMOS jumper, see “System-board components”.
2. Remove the jumper plug from the password jumper-pins (PSWD) and connect it to the CMOS jumper-pins.
3. Wait for 5 seconds and then replace the jumper plug to the password jumper-pins (PSWD).
   

    

Hi sadly this hasnt worked, same issue. Followed the steps exactly, any other ideas

Re: Every time I switch my PC on it never boots to Windows on 1st power on, it freezes at the Dell logo/screen goes blank

curious what happens if you disconnect all hdd/ssd from system, i.e., remove all storage devices.  now try cold start again, does pc always pass through Dell logo screen and then show “no boot device found” or similar error.

this test will hopefully elucidate a mystery.  If post is complete but pc fails to load OS (advanced program) on cold hdd start, it will always show error after you remove hdd.  If pc is stuck during post on cold start (before it gets to stage of loading OS), it will not show any error screen and will just stall w blank screen.  Given your report of Dell logo comes and goes, I suspect more likely the 1st cause.  If so, get a new hdd to test pc (first remove old hdd) by doing a clean Win 10 install on it.