Here's what I would do if the contents of the 1.5TB drive would fit on the new SSD.

1) Use Acronis (Torrent or $50 - or use a freebie like Clonezilla) to take an image of the 1.5TB drive (store the image on an external drive)
2) Restore the image onto the SSD
3) Change the boot loader in BIOS to boot to the SSD
4) Wipe the 1.5TB drive and use for storage

This is all assuming you're using the same hardware, and not moving the 1.5TB drive from one computer to another. You can always burn the ISO to a DVD and install a fresh copy of Windows 7 to the SSD. As long as BIOS knows where to boot from, you shouldn't have a problem. I would definitely wipe the MBR from the 1.5TB drive when the SSD is up and running with an OS to avoid any kind of confusion.

I have a 1TB RAID 1 (1TBx2 drives set up to mirror) for a storage partition, and at one time I must have installed Server 2008 on that and the MBR was still active. Talk about a PITA trying to figure that one out when dual booting my pc recently and playing with GRUB.

Good luck.