A clean install is better.
Also, if you are using Windows 7 64-bit, a 40GB SSD is too small. Get at least a 60 or 80GB SSD.
1. Connect SSD to the computer using one of the Sata ports;
2. Boot Windows from the HDD normally, go into disk management and do a quick format (don't do a full format);
3. Download or install utilities that came with your SSD; install latest Intel RapidStorage Drivers or whatever drivers the manufacturer of the SSD recomends; check if SSD is working fine; eventually do one or two benchmarks to see if it is behaving normally;
Note: if you haven't already, set the Bios to operate in AHCI mode, instead of IDE mode. SSD's work best in this mode. If you haven't selected this before installing Windows to the HDD, do it right before installing Windows to the SSD. Don't do it while still booting from the HDD, otherwise the computer will freeze at startup because Windows will not have installed the proper AHCI drivers. If you really want tot boot from the HDD using AHCI, there is a registry modification you can do, or even download a hotfix from Microsoft that will do it for you.
4. After being sure the SSD is working like intended, reboot, go into BIOS and alter the boot order, making the SSD first to boot within the HDD/SSD storage options;
5. Still in the BIOS, if you have it disabled, enable Boot from DVD-RW drive first, only disks after; Save and exit BIOS;
Edit: disconnect the HDD where the OS currently is. Kramy explains why in the post right after this one. Thanks to him!
6. Insert Windows install disk into DVD-RW and boot; select install OS to the SSD; install OS, etc, etc, until it is done;
7. Finally, to save space on you HDD, you can start thinking of deleting the Windows 7 installation from it and any programs you might have installed there. Sometimes that HDD has all the contents protected against deletion, so you should first go to disc's properties, security tab, and take ownership of it. After taking ownership make sure you have all the rights to view and delete files from that HDD.
And you're done. This way you can keep the entire library of Videos / Music / Photos on the HDD.
Oh, if you don't want to save anything on the Videos / Music / Photos / Documents folders on the SSD, just right click on each library's properties and remove the current location and select the location on the HDD.
You can also do it for the Downloads folder, so that each time you download something from the web, it is written to the HDD and not the SSD.
Hope that helps!
Enjoy your SSD!
Edited by tpi2007 - 7/25/11 at 6:19pm