Dell Inspiron 1545 is slow...

Hi guys, jux need a little help here again... My computer is a Dell Inspiron 1545 and it's going soooooooooooooo slow.  A little info about it: First of all the screen is broken I think, because when I turn on my computer I have to tap the screen in order for it to work [meaning to see the pictures] otherwise it's jux a blackish/gray/white screen.  Second, jux bought a new charger and battery for the computer.  So that's all that is new with the computer, so I don't know why it's so slow.  I rebooted to factory image already, and some stuff never got installed back to the computer.  I rebooted it to factory image like 5 times now, but it's so still slow.   I even tried everything from cleaning up all my stuff on there [which I have nothing and it's still slow]  deleted some programs, cleaned it, defragment it, [everything you could possibly do to make it go faster, but it won't go faster all all.  Still slow and freezes a lot [well basically all the time]

It's so slow, that I always have to restart it, and it always freezes to the point where I have to restart it too.  Do you guys think it's because of my screen?  Or do you suggest me to get a new harddrive?!   What will make my computer go faster?! Thank you so much!!!