I have an old dell ins 15 3500 series. Was running fine. I gave it to my friend who promptly lops passwords etc and somehow it is not what I set it up to me. She gave it back to me as she is totally lost on it.
Anyhow, as I could not for the life of me get into it, I was simply going to reset windows with my USB adaptor i have win 10 installed onto a micro SD. I have used this for several pc over 3 yrs and it is perfect.
So initial issue- it will start to install and then i get the partitions but they all tell me they are GBT and I can't install onto them. I figure no biggie, it is a boot setup error I made in getting it ready . SO i go into setup and it tells me i need admin password- NEVER run into this before, seriously. I use no pw whenever possible as noone uses my pc's but this was not mine to begin with so who knows. So after 3 attempts i am now locked out of everything and can do nothing at all.
I assume i truly just rendered my first pc useless?? It is 6 yrs old, a spare, not a biggie but I hate to give up. Thanks Guys!!

Boot from your Windows 10 installation drive. At the blue screen where you choose what to do, press Shift + F10 to bring up a command prompt. Then you can follow the steps on this website.

https://winaero.com/blog/securely-wipe-disk-diskpart-windows-10/

The bottom half of this page shows the commands to wipe all the partitions on a disk at once. After you have deleted the partitions, you should be able to install Windows 10 just like you would on a brand new drive.

Ok, I know I can get that far, so will try after church. Thanks

Using 'clean' alone should be sufficient - & finishes in an instant (& assuming you don't actually need to "wipe" clean the partitions).

'Clean all' can take a LONG time (depending on the size of the partitions).

Well.... Did that just fine. But now It will not boot with the usb at all. Gives the usb option in setup. That is what I have it set for . But in boot options, no USB option, HD, diskette, DRD, network. And UEFI boot manager. I cannot change anything as as I originally said admin password locked, but never had one..... I think i killed it.

Maybe something in the (Rufus) FAQ, https://github.com/pbatard/rufus/wiki/FAQ.

Also recall, https://www.pcqanda.com/dc/dcboard.php?az=set_linear_mode&forum=2&page=&topic_id=565337&prev_page=show_topic#565339.

Any chance you accidentally erased the flash drive too? Connect it to your working computer and look at it to see if it still has files on it.

No, it's good. I've always been able to figure it out before but this one may be too far gone .