computer stoped working screen just turns blue and says unknown hard error

[knowsnothing]

can someone please help my computer just stopped working i run in windows xp and now whenever i try to start it it just turns blue and says unkown hard error. i tried rebooting with windows 98 and half way through the installation another error screen comes up what should i do

 

[iss]

have you tried booting from your XP disk and doing a reformat and reinstall? How old is the hard drive in the machine?

 

[Char_X]

Your HDD seems to be broken... Try to plug in it to any other comp and run scandisk

 

[Spike]

Could you please post any code/number and/or filename that is presented in the error. That might help narrow it down a little.