[andrewas]

P4s are power hungry and run hot.

G4s are power hungry and runs hot.

HDDs are power hungry and can run very hot.

While a 250W can probably put out enough current to keep things running (While running very hot itself, natch) it probably cant make that current stable, hence the blue screens etcetera.

Get a new PSU, get a couple fans in there, and do it before something decides that its gotten too hot.

And you cant just pick up a cheap second hand PSU either, cos of that extra power connecter the P4 needs. And whats a new P4 PSU cost? £45, dont know in dollars.

And you want to look into some extra cooling a well. Its not just about fans - using round IDE cables instead of ribbon cables, keeping stuff tied out of the way, all that can improve airflow and thus cooling.

A lot of hassle to be sure, but what worth doing isnt?