Laptop Upgrade?

Don't know if I need a new one or not,it was second hand reconditioned when I bought it but it seems a bit slow and temperamental,or maybe it's just me.
Now I-tunes has gone a bit funny,when I import a CD the songs skip!!!!!!
Not really much of a tech-head when it comes to PC's, (if in doubt, give it a clout) should really learn a bit more how it all works.