[sAmI]

Hello experts,
                    I am trying to install Ubuntu on my desktop PC.I have downloaded ISO from Ubuntu official site. I have made a bootable usb drive. Now i want to install it in pre-exist C drive. A year ago i was installing it on my PC and unfortunately i lost all of my data. Installed Ubuntu in a whole Drive. I am scared of installing it. So asking here if it is possible to install Ubuntu in C drive alongside windows. is it possible to install it?

It's does not sound possible though, as he mentioned you should get a hard drive for another OS which would be more easy way to manage, Instead of creating Partitions. And about your VM Problem i ran into a similar problem have you tried enabling or disabling Virtualization in the BIOS Setting? And how are you trying to install the OS through ISO?
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I dont recommend that at all, i installed Ubuntu a month ago and i discovered that they use something like another hard partition type, i couldn't install back Windows on C before removing the whole disk from partitions and create a new disk again

It's not with Ubuntu i guess, I think every Linux (might not be) creates a different type of partition and for installing windows you will have to convert it to a NTFS or FAT Partition i believe so it can work again.