File system suddenly changed to read-only

I installed MineOS Turnkey on (according to that dmesg I did) Hewlett-Packard Compaq Presario CQ60 Notebook PC/303C, BIOS F.54 08/18/2009.
It used to be a laptop until the screen gave out, so my cousin ripped out all the parts and basically screwed them onto a plank. I’d been using that computer as my main one for quite a few years, when I finally got a new computer. It’s been sitting in the attic, collecting dust until a few weeks ago when my mates and I decided it’d be cool to make an adventure map together, so I decided to use that old computer to run a small server.
I’m planning on exchanging the HDD with an SSD when I’ve saved up enough and I’ve been trying to get my friends to help pay, so they too can profit, but to no avail… Ah well. Guess it’s mainly their problem; having a crappy server. (I don’t play on it myself that much)

Now I’ve seen the model number of the thing, I suddenly remembered I “inherited” another Presario CQ60, though that one it still completely functional (yet VERY slow).