HP notebook wont boot from Xubuntu live USB

I want to install xubuntu on my HP Pavillion notebook, but for whatever reason I keep getting a "No OS found" as return when trying to boot from USB. However booting from that USB on 3 other PCs works perfectly fine. So far I've tried flashing the bios to the newest official version, enabled and disabled legeacy support in the boot options and cleared all boot keys, reinstalled the xubuntu live USB and tried to install it using Unetbootin, neither of the above got me a working result.

Unetbootin gave me a missing file error instead:

File: \ubnldr.mbr

Status: 0xc000007b

Info(roughly translated from german): The application or OS could not load, because of an essential file beeing missing or is defect.