Can I upgrade the Intel Processor

Not if you have a 32 bit bus motherboard.

Sure will.

yes you can upgrade it

After checking the specs of this here : http://support.dell.com/support/edocs/systems/dim2400/en/sm_en/specs.htm

i can confirm that a intel core duo would not be supported without changing the motherboard, and probably the memory too.

Rytech Computer Services Limited

If I remember correctly Dell use a standard ATX MoBo

It is a bit of a crapshoot trying to upgrade a processor from a major manufacturer. Their motherboards are designed specifically for the manufacturer and documentation on exactly what will work NOW compared to when the unit was new is rather hard to come by. They don't support people upgrading very well compared to the aftermarket manufacturers.

You should go to dell.com and put in your service tag to check your exact configuration yourself before spending any money.

According to Dell, the Dimension 5150 has a motherboard that uses the Intel 945G Express chipset. You can see INTEL'S documentation on that chipset's capabilities here. According to that documentation you can use a socket LGA775 with up to a 1066 MHz system bus speed.

Looking at Newegg, the fastest LGA775 processor with 1066 MHz are a 2.93GHz Duo core or a 2.4 GHz quad core. Again, no guarantees either will work with your system, and you definately want to make sure your power supply and case cooling are up to the task.

Yes, you can put an E6600 or even a Q6600 in that bad boy if you want.

What is the service tag? Pentium 4 2.8 GHz is the fastest they put in them according to Dell, but not all of them have the hardware to support the 533MHz Front side bus.

Sorry that motherboard does not support the new core2duos.The motherboard installed in the demension e520 is an older version