Dell Dimension 4300 PC Processor upgrade

if the sci36-r13 is the stock mobo that came with that pc it isnt worth upgrading
pentium 4's use the LGA-775 socket this is compatible with all pentiums and core 2's (not includeing core i7), so you could put in a core 2 quad if you wanted to but it would not make much difference to performance because your motherboard would not be able to handle some of the fetures
your ram would also reduce preformance

if you wanted to upgrade that computer you would have to replace everything but maybe the case