Yes, you can use a SSD.
you WOULD NOT remove the HDD, you would just move it over to one of the other SATA ports (ref MB link posted by osamabinrobot ).
You would use the SSD as a OS (Win7) plus for your programs and then use the HDD to store all of your data and files.
Important - When you get the SSD, you will need to install window 7 on it. BUT MAKE SURE you disconnect the HDD until AFTER you install windows 7 on the SSD.
On SSD. The Minimum size for an OS + Program drive is 60/64 gigs, the recommended size is 80 or larger gig SSD.