Configuring BIOS in readiness for a switch to UEFI

essenbe said:

When you get to "Where do you want to install Windows" use the advanced options and delete all Partitions on the drive until is says 'Unallocated'.

I only deleted the system reserved and the Windows partitions. The data partition remained there.

Yes, sure. I did it nine days ago. All files in the data partition remained there after the clean installation in UEFI mode.

The OP, Dortmunder, may use a Linux Live DVD to convert MBR to GPT before the clean installation so as not to lose any personal files during switching from BIOS to UEFI.

Hi and thanks for all the advice. Post #10 from essenbe was particularly welcome – that was broadly the plan I was working on based on other threads I've been reading so it was good to see it 'verified'. The trouble with this kind of thing is the number of issues that may or may not arise during an install of this kind (BIOS to UEFI). The one I'm most unsure of is the conversion of the drive from MBR to GPT but I have this post to refer to when the time comes:
How to do a clean install with a USB-stick booter

My USB is indeed FAT32 so thanks, rpo, for thinking of that.

I have an SSD dedicated to the OS so preserving personal files is not an issue. I'm busy with something at the moment so don't know when I'll be doing the install, I'm just ensuring that I'm prepared. Thanks again for all the help.

That's it done and all went well. Apart from a terrible rattling sound when I switched on to begin the install. 'Here we go...' I thought but it turns out I'd nudged a cable against the CPU fan when disconnecting my two HDDs. My sincere thanks to everyone here who chipped in, especially essenbe, lx07 and Matthew Wai. I'm pleased that Matthew mentioned the F8 way of choosing boot source otherwise I'd have been doing it the old way - change boot order/install/change back again. Now all I have to do is spend the rest of the day and probably part of tomorrow installing and tweaking. Happy days...

Just out of interest, did the OP have to manually set 'Windows Boot Manager' (by drag and drop) as the first boot device under 'Boot Priority' after the clean installation?