I am trying to install a build of Chromium OS on my PC. I do not have any spare disks or flash drives. I want to find a way from installing the .iso from Ubuntu Live CD. How would I go about doing this? My friend suggested mounting the .iso, but I don't know what he's talking about.
Unetbootin will set up grub2 to boot an iso directly from your hard disk.
potentially you could use QEMU to attach your real harddisk inside a virtual instance booted off that .iso you are willing to install. can be a bit tricky but it worked for me.
once booted from Ubuntu Live CD install qemu:
then download Chromium OS iso. run QEMU telling it to boot off the .iso and use your real harddisk.
i have to warn you though that this might screw things up. you would be safer off by only using a partition of the harddisk dedicated for the install of Chromium OS. you might need to do some bootloader configuration if you consider installing on a partition.