WIN7PESE / UEFI /WINDOWS 8

I want to run Win7PESE from a USB DVD Drive on a Windows 8 Computer to clean a malware infection.

The laptop is an HP Envy Ultrabook 4, and Windows 8 pretty much hijacked the boot options (UEFI boot). Took a while to access the Bios, since I had to press escape, then F9 and then F10 to get there (If you press F10 directly it sends you to the Windows 8 UEFI boot screen). I enabled the compatibility support module (CSM), required to boot with an Older OS and disabled the secure boot option.

Despite changing the booting order to start with DVD (Usb in this case), it won't load the Win7PESE disk and will go directly to the Windows 8 screen.

Can you run a Win7PESE disk on a Windows 8 PC or do I need a WIN8PESE disk ?

You can have the UEFI boot with Win7pese x64, it is integrated by default. There is no UEFI boot with win7 x86. What architecture do you have?
Otherwise, there is no problem to run Win7PESE disk on a Windows 8 PC.
I do not have UEFI hardware, to guide you well. just tested in Virtual Machine. You should be able to use "Copy to USB-Device BCD", Rufus  or other Tools to make your USB.
Look at fuwi's post : UEFI Secure Boot

About Win7pe or Win8pe choice.  Win7pese is fine, if it suit you, there is no real necessity to go to Win8pese except for native USB3 or for increased hardware compatibility. It is maybe a little bit faster. A matter of taste, also.

So basically I need to use a 64 bit version instead of the 32 bit?

Yes, x64 is required for UEFI, either in Win7PE or Win8PE.