HP Pavillion w/asus motherboard PSLP-LE won't enable boot from usb

I'm trying to boot from USB to install a windows 7 professional OS on reformatted and repartitioned HDD using a bootable USB made with Rufus. I usually do it this way because CD hash counts are wrong or cheap CD won't complete installation give an error message about a driver missing. I know this is a hash count/Cd quality issue because I use the same iso file to load rufus and it works when the bios recognizes the usb in the boot options. I can't get this bios to recognize the usb to include it in the boot option list either through setup or f10 boot menu options. Everything regarding usb (legacy etc) is enabled in bios.I was wondering if it is fixable in this HP Pavillion with this particular motherboard either through bios update or any other method available. It's a 2007 HP Pavillion desktop.
Thanks for reading and if someone knows the secret I'm all ears (fingers and eyes too).
CD

Does your mobo have UEFI? If so what are the settings choices for UEFI, EFI, CSM, Legacy BIOS, Secure Boot, etc? Is there a more recent UEFI (BIOS) firmware update?

Try disabling Secure Boot, Legacy BIOS, CSM then installing using Rufus formatted stick for UEFI to GPT disk. UEFI Bootable USB Flash Drive - Create in Windows

Boot the stick as UEFI device only. Delete all partitions to clear any MBR formatting. UEFI (Unified Extensible Firmware Interface) - Install Windows 7 with - Windows 7 Forums

gregrocker said:

Does your mobo have UEFI? If so what are the settings choices for UEFI, EFI, CSM, Legacy BIOS, Secure Boot, etc? Is there a more recent UEFI (BIOS) firmware update?

Try disabling Secure Boot, Legacy BIOS, CSM then installing using Rufus formatted stick for UEFI to GPT disk. UEFI Bootable USB Flash Drive - Create in Windows

Boot the stick as UEFI device only. Delete all partitions to clear any MBR formatting. UEFI (Unified Extensible Firmware Interface) - Install Windows 7 with - Windows 7 Forums

None of that.It's Legacy only. The choices are limited. I can change from ACHI to IDE or RAID but that won't help. I figure the only option is a bios update but I haven't found one yet.

Then work through the steps to Troubleshoot Windows 7 Installation Failures - Windows 7 Help Forums

gregrocker said:

Then work through the steps to Troubleshoot Windows 7 Installation Failures - Windows 7 Help Forums

Thanks Greg but it's really a moot point since I found a statement by HP that if your bios doesn't have the option to boot from usb then you won't be booting from USB. In other words I will have to try another source . I was thinking maybe boot from external drive. I'll try that. This MB is not even as semi-sophisticated as the nettle was. At least I could boot from usb but if there was a usb plugged in the start up would just halt until you pulled it out. Weird.

Often the stick is formatted incorrectly. For example you would not use Rufus to format a non-UEFI stick. Use the tool prescribed in the clean reinstall tutorial. Until then it cannot be said with confidence that your BIOD will not boot flash stick

Often the stick is formatted incorrectly. For example you would not use Rufus to format a non-UEFI stick. Use the tool prescribed in the clean reinstall tutorial. Until then it cannot be said with confidence that your BIOD will not boot flash stick

Why can't you use a DVD? If necessary can you borrow a USB DVD drive to try it?