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Was attempting to do a clean install of windows 11 on xps8700 using same USB that just used to update a dell inspirion 3520.  
for some stupid reason i followed a web post to switch to legacy boot.  This turned in to a disasters can no longer boot into my OS and can not get back in to Bios to change it back.  Looks like I may need to reset the bios somehow

Symptoms are

When booting regardless of hitting F2 or F12 it goes to a screen for Intel with info a Raid volumes and then goes to a second screen for Ethernet controller then goes to reboot system. which goes back to the first screen and cycles over again continuously.

this is an apparent boot failure as does not see the F2 (and F12 does the same thing).  I have used two known working keyboards (USB)

Twice have seen a momentary support assist screen with option to go to bios setup with Alt B or B but have never been able to get it back and do not know how I caused it to appear.

Can I reset BIOS to default somehow?

Any suggestion or guidance appreciated.