What you have is a RAID 0 with the hard drive and the SSD or iHyou are just using the SSD as cache?
If what you have is a RAID 0 with the hard drive and the SSD most likely the RAID structure got corrupted in the hard drive. If you are just using the SSD as cache then you can access the Option ROM by pressing Ctrl+I during POST and then set the SSD as non RAID.
Bear in mind a RAID 0 cannot be rebuilt so; if the RAID structure got corrupted then the information will be lost.
till yesterday, my system was working perfectly. I also have HDD+SSD for cache.
Problem started here .....had preinstalled win 8....removed it...installed ubuntu....thought that i can use ssd to speed up....opened IRST option ROM as it always prompted me on startup....deleted the RAID....created a new volume...set the space for the volume....restarted..and boom....error"PXE-M0F exiting PXE".....what to do ?