Dell Dimension B110 use two hard drives.

I have a Dell dimension B110 

My neighbour tossed out a Compaq Presario SR1303WM, it has the same type hard drive connectors I/DE it has a 40 gig hard drive. 

Could I use it as a second hard drive to boot up and use my current  hard drive until I get a larger 250 gig -500gig hard drive.