1337x :
In my PC I have an SSD which has my Windows 10 installed on it. In addition to this, I have a 1TB HDD as a second hard drive.
My problem is that I cannot enter the UEFI BIOS because the SSD with Windows installed is MBR instead of GPT. Basically, If I go to BIOS and set UEFI as my boot option, I will get an error saying that there's no Operating system installed and this will cause a boot loop until I set it back to Legacy BIOS.
Is there a way for me to convert my Windows on the SSD to GPT without formatting it and losing my WIndows 10? I don't mind losing information as long as I don't lose my Windows 10.
If your PC has a choice called UEFI boot, it is already showing you the UEFI bios. It won't look any different to what you already had. All motherboards in last 9 years have had UEFI bios.
Its like this, any BIOS that allows you to choose a legacy option is a UEFI bios already, as prior to UEFI there was only 1 way to format hdd, so it wouldn't offer a choice.
https://en.wikipedia.org/wiki/Unified_Extensible_Firmware_Interface
You don't have two BIOS, legacy & UEFI., You have just the one, its just UEFI can emulate the BIOS features so older systems such as Win 7 can be installed on it using MBR, and not notice any differences. UEFI is so much more than BIOS, it has features BIOS didn't and is by design modular so it can be altered to grow as PC need more features. Also lets you have a Graphical User Interface in the "bios" that knows what a mouse does.
What you did was swap from
legacy boot method to UEFI boot method,
it didn't change the BIOS itself.
I wish I had seen thread prior to you following the advice as you already had what you wanted, you just didn't know it. Shame no one else thought about it either.
GPT also isn't of great benefit to the disk sizes you have, its main advantage over MBR is it can access drives bigger than 2.2tb (much bigger, 18.8 million Terabytes is the max size it can access, largest drive now is a few 100 terabytes in size). I mean, its not a bad choice but only as now you can have up to 256 partitions on the drive if you wanted, MBR only allowed 4.
System reserved isn't a new drive, its a new partition probably created during the GPT conversion
show screen shots of disk management here (upload to a image sharing website and share links here) instead of new thread as it shouldn't have a drive letter, so should only show in disk management.