blue screen error

Hello… i have an acer, windows xp desktop
my computer has a blue screen error when it loads….
before I could get into safe mode but now it will not even boot in safe mode.
The blue screen reads "slang"– your computer has been shut down to protect it, please uninstall any anti-virus protections,,,,,…other people say it is the hard drive, but the computer will boot up but won’t go past the safe mode selection screen.
How do I fix this problem?
Any responses will be greatly appreciated…….

Thanks!