computer shuts down to black no signal screen
I have two P4 computers that have died about a month apart. I thought power supplies were the problem so I replaced them but they still die at random times and some times at start up.
I get no warning except that one makes a series of chirping sounds either before, during, or after death. The other just dies silently.
I have run Western Digital hard drive diagnostics and both check ok on all tests. I have run Microsoft memory diagnostics and both check ok on all tests. I have reinstalled from scratch the op sys on both and it doesn't help.
When these die, they just stop and go to black screen indicating no signal. There are no blue screens or error codes of any kind. Both use on-board video. One is a Dell and the other is a Jetway system.
When they do get up and run, they run flawlessly. Sometimes they will go for hours and other times just a couple of minutes before death. Sometimes they just won't start up and it is always just a black screen stating no signal.
There is not fan or hard drive noise when they die. They just completely shut down as if you turned off the power.