Some questions about Installing UEFI and data created in the past

First of all good day everyone! I have some question to ask after telling you the situation and I will put it with numerical order below.

I have a system running Windows 7 Ultimate 64 bit on a A6 6400k processor and MSI A88XM-E35 Motherboard which I think capable of running Windows 7 Ultimate 64 bit UEFI? And recently I figured out that if that board is UEFI ready, I did installed my Operating System wrong way if I want UEFI. That's because before I bought the Motherboard I was just learned that almost all new motherboard in the market today are capable of a features called FAST BOOT and don't know much about different installation on this new system called UEFI. So when I was installing my Operating System which is Windows Ultimate 7 64 bit, I installed it in traditional way which is booting it from flash drive that I created from winsetupfromusb 1.0 beta 8 and it was formatted also from NTFS and I did not realized that only Fat32 is supported. Then after that I installed drivers from driver pack solution 14.8 but I observed the features fast boot I was looking for looks like not functioning because when I boot the system and observed the time it used when booting is just the same. So I went to my motherboard manufacturers website and saw the Utility driver for Fast Boot Features and installed it but after that I realized the same thing it's not working. That's why I search around the Internet and learned all these things.

And now I want to re-install it, but this time in the right way with UEFI. So I created another bootable flashdrive from winsetupfromusb 1.4 to be use and make it right. But still I didn't know these things below:

1. As you know I have my current OS Windows Ultimate 7 64 bit in my one physical drive with two partition called drive C and D. The drive C where the OS resides and in drive D I put a lot of files there and I don't wanna touch it if ever I want to re-install this time with UEFI. So my question is, it is possible that only the drive C I will delete partition and install there the new OS Windows Ultimate 7 64 bit UEFI?

2. So if the answer in my first question is possible. Will the new Installed OS Windows Ultimate 7 64 bit UEFI could read/write the files in my drive D which is created by OS in the past on this computer?

3. Btw I also managed to successfully update the BIOS driver via MSI Live Update 6. My question is what will happen to the bios if I re-installed with new OS, will it be roll back to the state when it was before I update it? Will it affect the condition of my new install OS? Should I restore it to factory settings before installing new OS again? How? If it should not restore to factory settings, do I need to update it again from MSI Live Update 6 after installing the new OS?

Thank you very much and please forgive me asking my questions in novel way.