HELP!!! w/ipod to an existing itunes file

Hello,
A little backround before i jump into my problem. Couple years ago my computer crashed so i was no longer able to download songs into my ipod. Recently my parents bought a new computer so they passed their older one down to me. This "hand-me down" computer still has their old itunes forlder w/ all the songs that they have downloaded.

My problem:
I hear some of my friends saying that if i were to plug in my ipod into my "hand-me down" computer, my songs would be earased and all my parents songs would replace my songs. HELP A BROTHA OUT!!

&

Would this help? if i were to earse the itunes and re-download itunes using the cd software that came w/my ipod.

-A-sal
aka
beast from the middle east
aka
the man who INVENTED Thomas Jefferison