aldan :
what are your computer specs?what windows are you running? is this the full error code? anything lead up to this ie downloads,software installs etc? sorry man,but my crystal ball is broken.we are not psycic here.we need the whole story.
I have a HP p6-2100z desk top and AMD E-450 APU prossor at 1650MHz.
with windows 7 64bit operating system. I hooked up a 1TB external hard drive and tried to boot from it. That's when it started. I have removed the external drive.
I did the HP hardware diagnostics test and the CPU passed,the hard drive passed,the memory test passed but the boot test failed and shows the error code 3fo and says no active partitions. All I get now is a black screen with the cusor blinking in the top left corner of the screen.
Need anything else just ask.