Any idea what killed my Mac Mini?

I got this Mac Mini (1.5GHz Intel Core Solo/512MB SDRAM/60GB HD/Combo drive/Intel GMA950 GPU/AirPort & Bluetooth) secondhand around seven years ago. After a while, it became very slow and I needed to get a whole new computer, but it still worked (and was stored in its box for a good four years).

I plugged it in today, and tried to reinstall 10.4.7 from the disc it came with - to no success. I wiped the HDD, ejected, unplugged, diagnosed, restarted everything. I always got the "Alert - this software cannot be installed on this computer" dialog after the language selection prompt.

After finally being able to get the installer disc out, I tried to put linux mint on it - and that was when everything went wrong. Now it won't turn on, at all, no response to the power button, no startup sound, no noise from the optical reader, no anything.

(I wonder if getting the linux disc out would change something, but every article and tutorial on getting stuck discs out assumes that the device can boot up which mine can't.) I might have messed up with the way the disc is burned and such, even though I tried to follow instructions and methods online.

Was it the linux disc that fried something? Was it too much for such an old computer to be rebooted every five minutes and that killed it? Is it worth to pay for it to get fixed (if it can be fixed, that is...)