[chav1]

sounds like a hardware fault rather than software related problems

pcs locking up can be a few things ranging from iminent hard drive failure , faulty power supply

i doubt it is your memory/ram as it wouldnt normaly boot up at all if it was the memory but hard drive failure can come on gradualy and also power supply units may fail as they get hotter

switch your pc on ans see if the fam in the power supply is spinning around

always a bad sighn if it is not as your pwer supply is no longer geting cooled