There are a few steps necessary to copy, or "clone" an existing Windows operating system from a hard drive (HDD) to a SSD without reinstalling the OS.
It is not possible to simply copy one hard to another and expect the operating system to work, since there are hidden system files and partitions, boot partitions (or a MBR) that cannot be copied. The steps necessary to clone a hard drive are outlined below.
1. Clean up the old drive from junk/temp files, etc., you can even disable System Recovery and the Page file temporarily. From Windows Explorer, right click on the "C:" drive, choose: Properties > Disk Cleanup > Clean up system files and delete all unnecessary files. Uninstall unused programs from Control Panel > Uninstall Programs.
2. Try to shrink the OS partition from Disk Management, so all partitions are small enough to fit onto the new SSD. Navigate to Control Panel\System and Security\Administrative Tools > Computer Management > Disk Management. Find your OS hard drive, note all partitions, and try to shrink the usable C: drive. The idea is to have all existing partitions to fit onto the new SSD. If this is not possible, you can attempt to do that with one of the cloning utilities in the next step.
3. Use a free cloning utility software, we recommend Macrium Reflect, of EaseUS to clone the HDD. You can shrink some of the volumes with newer/better cloning tools. Some utilities may require the use of a USB Flash drive to boot the computer so that the OS drive is not in use while being cloned.
4. Disconnect the old drive, plug-in just the new SSD, make sure BIOS is set to boot from it, and start the PC. It is best when working with only one bootable drive at a time, and you'd have to check the BIOS settings to make sure the SSD is recognized, and marked as one of the first bootable options.
5. Reconnect your old drive to use as storage. Once everything looks ok and you have a working OS on the new SSD, you can re-enable the Page File, system recovery, etc. You can also hookup your old drive to use as storage, just make sure that the BIOS doesn't use it for booting.
See also:
SSD Speed Tweaks
