|If the screen is jumbled when installing from the CD then it probably is not the fault of the hard drive. Sounds more like a defective video card/chip. |
I suppose a power supply that is feeding the wrong voltages could cause problems like that also.
If the computer does that when it is totally cooled off then that should eliminate overheating. Although a defective CPU cooling fan or improperly installed heat sink could allow almost immediate overheating.
Open the case and first look for axcessive dirt/dust that could impair the fans and the cooling. Then try starting and see if the fans are all rotating as they should, especially the CPU fan.