computer shutting down

[biggy]

hello all..new to forums..i have avery confusing problem with my pc..it keeps shutting down when i open up an application suck as adaware,photoshop, even my games
i thought it might be my power supply so i went and bought a new 400w supply to no avail..after it shuts down it emits an audible tone high, low, high, low, high, low, and continues until i unplug my power supply cord..after this happens i have to wiat about an hour or so before i can even get back to desktop..its like if it encounters a load (opening applications) it shuts down..but not all the time..some nights i can stay on it for hours without it doing it but others 10 minutes tops and it shuts down
the specs are as follows:
machspeed 400dbl mobo
amd xp2800
512mb 333 fsb ddr pc2700
geforce 4 ti4200
western digital 80gb 7200rpm
any help would be appreciated

 

[Joeisalsocool]

Which power supply emits the noise. By far far chance, the new one could also be bad?

 

[ShoobieRat]

Sounds like an overheating problem. You're getting a ooh-wa tone when it fails?

Check your CPU heatsink, and make sure all your cards and RAM are seated good (take them out and re-seat them to be sure).

If you could identify where the sound's coming from, that would help. I mean, if it's a fan, I would suspect a mobo power problem. If it's actually a tone coming from the onboard speaker, then you're getting a motherboard message. If so, check with the manual for any sound codes.

 

[cnico88]

That happened to me once and for some reason it was the Cdrom which was not working properly, try removing your external devices.

How long have you had this problem? Did you just build your pc and it did that?

 

[biggy]

yes i am getting the ooh wah sound..it seems as if it is coming form the onboard speaker kinda towards the back..both power supplies have done this
i built this pc over a year ago and it has just started happening about two months ago..at first it would shut down about once a week..now it does it once a day..if i'm lucky
i dont know if overheating is the problem..i got a volcano monster fan on my processor..ram fan and hardrive fan, so all is nice and cool in the case
i was told it may be my ram going out..i dunno i get teh "ram beep" at startup ..but like i said it only really does it when the pc is under a load (opening applications, gaming, even slow websites)
thanks for all the replies..this has just got me stumped