Convert MBR Disk to GPT Disk

Need some help...my SSD has 3 basic MBR partitions (C D E)...partition C is the System Drive and I want to convert these partitions(DISK) to GPT..I found a program AOMEI Partition Assistant that is able to convert MBR to GPT without data loss, but it doesn't work because it can't convert system drives...I want to somehow convert partion C to be a normal drive so that this little program can convert my disk to GPT...I know that I won't be able to boot again, but that is not a problem I was going to install Windows anyway....I just want partitions D & E to be intact and GPT.
I know I can unplug my ssd and go to a friend with a PC and just format drive C and then convert the entire disk to GPT...but nobody has a PC anymore.

Brink said:

Hello Catalin,

I'm not sure that's possible on a system drive without reinstalling the OS with UEFI so it will be able to boot from GPT. This of course would mean formatting the hard drive in the process though.

An easier option would be to get a second hard drive, convert it to GPT, create two partitions on it to use for D & E instead of them being on your system drive. This way you could just copy over the contents without losing anything.

Hope this may help some. :)

I went to a friend(found one with a desktop pc) with my SSD and formated C drive and converted the entire disk to GPT with that program(works 100%)...reinstalled windows to C drive and now everything works(I just wanted to test a feature in BIOS-Ultra Fast Boot)

Tried to do this to a 250gb SSD coupled to a laptop (Window 7 Home Premium) logged in as Admin. All went well until the final step when the alternative "Convert to GPT disk" just didn't appear on the right click menu.
Any suggestion would be appreciated.

OF/O2OF

Thankyou very much for the innput. I have tried again using the elevated command prompt and went back to MBR.
I hope that the installation will be successful.
Thanks again.

Well although everything looked to be OK MBR wasn't there.
I have coupled the ssd back to the laptop where it appears as drive F

I'm hoping to find the right comand to direct fdisk /mbr at this drive. (I'm of course no racer where DOS is involved.)