computer problems

Don't you have P4 1.8 512 128? That's good enough, unless you're prepared to do all that work.

i have 1.8 256 and a 20 gig hd, i have a really low p4 so chances are this comp has a faster processor, more ram, and more space because my brother's friend has a decent amount of money, it has a dvd rom for one drive and a cd rw for the other, both things i would really like

ok i dont know what i did but now when i try and turn it on, the smallest fan turns and the comp makes a clicking noise and the motherboard light flickers when it clicks but i have to hold the power button down

Double check the case to MB connectors. Make sure you have them in correctly.