pc freezing up

[theted]

[TazUk]

Try running a memory test, you'd need to download something like for this

[davey6]

you don't say what windows your running.

i think the early CELERON chips use to freeze and not shut down if they over heated.
they did not have the full protect like the p4 which shuts down the system i am pretty sure they would just lock up.

check the heatsink and fan on top of the cpu.
make sure its running feely with no noise , and no dust has built up in the heatsink stopping the airflow of the fan.

windows will run in safe mode on a hot cpu as its not loaded any device drivers your just looking at a vga standard desktop.