Sims 2 insert correct disk help

Hello,

i have a copy of the Sims 2 with no expansions and i got it all installed just fine, but when i go to play it i get the insert correct cd/dvd and press ok to restart message that everyone is getting.

i have an Elitegroup Co. I-Buddie4 notebook
with windows 7 home premium
1 gb ram
intel pentium 4 cpu 2.00 GHz
with 32.0 GB free space on my hard drive.

can anybody please help me??? im going insane trying to figure this out!!!