Go to About This Mac under the Apple menu then run System report (or System Profiler in older OS's). Then select Serial ATA and review the Partition Map Type of your SSD drive, it should be: GPT (GUID Partition Table). If not you will need to reformat it using Disk Utility app. and reinstall your OS and other files.
If it is the correct format type did you use the System Preferences Startup Disk and bless the SSD as the startup disk? If your system has two volumes with bootable OS's you must tell the system which one to use.