If you were moving from SSD to SSD I would recommend Macrium Reflect free version. I used it when moving from my Plextor to my Crucial and it worked great.
Going from a HDD to a SSD is bit more complicated. I think it has to do with partition alignment or sector size. I can't remember someone might know of a program that can do this though. I think the general advice for best performance is doing a fresh install.
I'm not sure how the upgrade key works. You may have to install/update Vista and then upgrade to 8.1. That would be a huge hassle and a long night.
You can get an ISO of Win8.1 from Microsoft using this link. Click on the purple "Create Media" button and follow the onscreen instructions.
http://windows.microsoft.com/en-us/windows-8/create-reset-refresh-media
It's true -- there are some feasible ways to do everything for free, and there are some times you weigh the complexity and misery of one path against the expense for some useful piece of software.
Acronis -- both Disk Director 11 upgrade 2, and True Image 2014 and possibly earlier -- will properly align the SSD without user intervention. You can test for alignment through the command prompt, and do some arithmetic based on hexadecimal logic -- divide a numeric result by 16 (or was it 4096?) to see whether there's a residual. But if you know the software takes care of it, you needn't bother.
There is another utility that will clone an HDD to an SSD (I'm pretty sure) called 'Parted Magic" with a permanent license and bootable-CD creation feature for $5.
If you can clone, why -- then -- would you want to reinstall and re-upgrade?
I can advise how to prepare for it: First-- clean up as many red and yellow events as you can in the event logs, or determine which are benign. Clean up your registry with a registry cleaner like CCleaner. Run a thorough CHKDSK on the HDD; run SFC /SCANNOW, to make sure there's been no OS corruption. Defragment the hard disk, then turn off the hard disk defrag scheduling.
All but the last item should have been routine maintenance anyway . . .
Then, clone the HDD to the SSD. You'd likely choose the option to shut down the computer immediately after completing the clone. Then remove the HDD unless you want to reboot into a CD-bootable disk utility to delete the HDD partition, create a new one and re-format. And you might choose not to do that if you wanted to keep the HDD as backup, at least for some short time.
