weird noise

[hammerfox]

Hi guys,

I've been having this computer for about 3 years now. Recently, things started to get abit weird.
Everytime i switched it on, i would make a "fire engine" noise and nothing would come up in the screen, but other times it would start up perfectly fine.
This problem has start to get more and more often. Nowadays im not able to start the computer at all.

Secondly, when i have entered windows, it can suddenly make the "fire engine" noise and shut down by itself.

Has this got to do with the CPU or is there a hardware problem?

I have tried
- connecting only the CPU/Mobo/RAM and it starts fine
- Adding the DVD-ROM (fine)
- Adding the HD; it shows the BIOS but doesn't enter windows (the windows logo is not shown)
- Checking the VGA card (fine)
- Checking the power supply (fine)
- Checking the pins for fault (fine)
- Checking the HD on another comp (fine)

Thanks for your help

[Jason]

Run a <a href="http://www.memtest.org">Memtest86+</a>
Download the bootable floppy version. It will check your RAM for errors.
Post back the results and we'll take it from there.