Had my asu m4n78-pro mobo for just over a year now and when I first did the setup of the system what I noticed is that my mobo would boot up but would never beep, it would boot up and run but until today it never ever gave me a beep and I have tested my system speaker and I am sure it works and that I am connecting the speaker correctly on the board. let me also add that for a month now I have had random issues and last week I found out that the ram was bad so I replaced it and every thing worked for a day. also during this time I started having a new issue where the system would boot up and every thing works but there was no system power light (that's the green light thats connected to the front of the case that comes on when the system turns on). also the mobo has a green light that lights up whenever the power supply is connected and that light works correctly.
so my problem now is when I hit the power switch all system fans power on but system won't boot and case power light stays off. sometimes the cpu fan would spin up then stop after about 10 seconds.
I have tried a spare power supply that I had so I don't think that's the issue
let me also mentioned that the ram I got is not on the mobo's recommended list however I don't think it's the ram as it worked perfectly for a day .
I have also tried the old stick of ram that I know was an issue because I ran mem check and it showed some errors however when I had in the bad ram the system would still boot atleast to bios so I know it should work even if the ram was bad.
Well thanks for all the help. Any ways, I read a post online about symptoms of a bad cpu and I noticed that I was having two of such symptoms, one where all fans would spin up when I power the system on and would continue to spin at max speed and the other where system boots with fans spinning then shuts off on it's own.
So I took my cpu out and got it to a shop to get it tested, and guess what my cpu is dead..
so I will be getting a new cpu soon.....
for anyone who might find this useful, I would recommend to never use the stock fan that comes with your cpu, and also if you ever get a cpu fan error at bios boot screen please take it seriously.