It has a 2.8 Ghz Pentium 4 CPU. So it is a socket 478. The first P4 CPUs had socket 423 (Called Willamette if I'm right) and where limited to 2 Ghz.
It might be Socket 479. For the record, Socket 479 and Socket 478 are not electrically compatible. Socket 479 has been Intel's mobile socket for some time now.
Do you think that I can replace it with a Core 2 Duo T series processor? Cause I saw they're socket 479 as well...
I really need to be sure about the processor compatibility... would a Core 2 Duo T series fit into my HP as you said it's socket 479?
You'd have to ask HP. Also, it may not be a "user serviceable" part. You may be able to get to it, but doing so may void the warranty.
Who cares about the warranty? I bought it 4 years ago! That's why I'm not sure whether the new processors fit the motherboard.
Well, given the age, I'm quite sure it wouldn't work. At the very least, the voltage requirements Core 2 requires would be different than what were available. Feel free to try it, but I'm quite confident saying it wouldn't work.