Please, help me, I really need it. I have laptop Lenovo Legion y530H, it is quite problematic laptop for linux but I installed it with official guide.
Laptop has 1000Gb hdd and 256Gb ssd.
I used 500Gb hdd + 100Gb ssd + 16Gb ssd for swap.
I wanted to use hdd for storing mediafiles and ssd for everything else. But I don't remember how ssd was mounted: as / or /home.
Everything worked excellent. But today I decided to install windows, downloaded iso, created boot usb, went to bios and set 'use efi first' and set my usb at first position. When windows asked to choose a disk I tried to choose last 100gb on ssd but Windows could not to be installed there, so I chose 500gb hdd. But had error windows can't be installed because this disk use mbr but windows need gpt. So I opened terminal and executed
diskpart
list disk
select disk 0 (hdd)
clean
convert gpt
exit
Yes, it deleted all my files on hdd but they are not important. After that I installed windows on hdd, restarted laptop... and can't find ubuntu.
I really need your help because I have important data there. Which solutions are good for me:
- recover old system <- the best solution
- somehow upload important data to cloud, remove everything and reinstall linux again (windows doesn't matter)
I thought that second is possible with 'ubuntu test mode' so I created boot usb with the same version ubuntu (18.04lts) but after few seconds loading it just freeze. I don't know what to do. I tried two programs to create boot usb: mac balenaEther and mac uNetBootIn and formatted usb to mbr fat.
I hope somebody here know how to recover old linux after changing mbr to gpt.
P.S. When I try to load from boot usb I have next errors, then logo of ubuntu with loading which freeze after few seconds: 
