I know this may sound odd but give this a try. Remove all hardware except what is needed for the computer to actually run. If you have USB cards, modem, etc remove them. The only thing that should be installed is dvd drive, hard drive, mobo with processor and ram. If your mobo will run with one (1) ram dimm, install one (1), and if there are multi-hard drives, just use OS drive. Unplug all others.
Just the bare minimum. Then try your install again. Make sure you have a backup of all data you deem important.
Your last reply stated you are using a Pentium 4. Is the version of Linux Mint 12, 64 bit or 32. If your trying to install a 64 bit version of Linux Mint 12 it may be incompatible with your P4 processor. I believe they are 32 bit unless it is stated. Try the 32 bit version of Linux Mint 12 if it works, begin reinstalling your hardware one (1) component at a time rebooting after each device is installed. This will inform you of a bad or faulty part.
I'm still grasping for straws but I hope this helps. I'm hoping that it works with the 32bit version. I would download and try that before any of the other solutions given.
Multi-Boot Linux Mint 12 (lisa) x64, Windows 7 Ultimate x64, and Mac Os X 7.3 Lion x64
Mobo - Asrock H55M-GE
Proc - Intel I7 860 x4 @ 2.8ghz
Graphics - ATI Radeon HD 5770 1GB DDR5
Memory - G-Skill Ripjaws DDR3-1333 8GB
Hdd - 180gb SSD, 2x - 2TB in Raid0