done this several times myself, easiest and quickest thing to do is clone your existing HDD onto the new SSD, then just boot up from the SSD. no need to reinstall or reactivate anything, no loss of preferences or settings...
i'm not going to hold your hand, but here's the gist of what to do:
1) ensure you purchase a SSD large enough for your needs and current usage. if you're currently using up 80gigs on your HDD then you'll need a SSD of at least 80gigs, post formatting obviously.
2) download and install the free edition of easeus partition master
3) using easeus, shrink the c: partition down to SSD size, even smaller just to be sure (ie, if you bought a 128gig SSD, shrink c: down to around 100gig). windows' built in disk management might be able to do this, but i find it usually never lets you shrink a system partition as much as it could.
4) plug your SSD into the computer (sata preferably, but via USB adapter works fine too), you'll have to restart the computer if it doesn't support hot-plug/ahci.
5) using easeus, clone your existing HDD onto your SSD, click the shutdown after completion box. if it asks you something regarding making the SSD bootable click yes. this will only be a few minutes over sata (over an hour using USB)
6) when it's done and shutdown, take out the HDD, replace it with the SSD.
7) bootup! (you may have to reconfigure boot priority in BIOS, maybe not)
8) now that you're up and running on your SSD, use easeus once more to expand the c: partition into any unused space (or windows' disk management)