Hi and welcome to forum.
Are you running in AHCI mode?
Did you install latest RST driver (and all neccessary drivers)?
Second can be memory.....3x2GB ?....give me more detail.....7-7-7-21....but what is frequency?
1TB should be no problem at all (I have same model).......or I am afraid that your HD is gone (as my,after 1 year...and I using only for storage).
Try to run CrystalDiskInfo.