Ok. Sounds crazy, but it works.
First, you'll need to identify which Sata port is which, you want the SSD in Port #0 and the HDD in Port #1.
After identify, leave the HDD in Port #1, but unplug JUST the Sata cable from Port #0, leave power to the SSD plugged in.
Hit the power button and leave the pc powered up for 10-30 minutes.
Do NOT turn power off, just plug the SSD Sata back into Port #0.
This will fix the issue, its a Crucial firmware issue where the SSD dissappears from the boot priority list, so your HDD becomes listed as primary boot, then swaps when the SSD gets recognised. That is quite common and Crucial's own site has a fix, but it's not reliable.
After doing so, check your bios to make sure the SSD is listed as primary boot (or at least is in line before the HDD).
Lastly, take a visit to Crucial and upgrade the firmware to at least version 10g
Hope that helps.