dell 2400 dimension making weird noise

Can you help us help you.  We need a little more than "it's making a noise" to try and help you.  e.g. is it a high pitched fan noise, or a screeching noise, etc.  

Does the PC actually start OK, just that it's making the noise or does it start the initial Power On Self Tests but will not load Windows?  

Hi Erikuack :emotion-1:

Look on the back of your PC and are there any lights lit on the 1234 diagnostic lights.

Run the DELL DIAGNOSTICS.

Shut down (see page 18) and restart the computer.
2 When the DELL™ logo appears, press immediately.
3 When the boot device list appears, highlight Boot to Utility Partition and press .

The do a Express Test.

Try this.

RUN CHECK DISK —
Windows XP
1 Click the Start button and click My Computer.
2 Right-click Local Disk C:.
3 Click Properties.
4 Click the Tools tab.
5 Under Error-checking, click Check Now.
6 Click Scan for and attempt recovery of bad sectors.
7 Click Start

Check back if you need more help.

Look inside and see if it looks okay if it is do this

Have you tried a air duster on the heatsink and fan inside the computer. Are you okay to open it up.