I have a Sony Vaio VPCEH35EN 3 years old laptop, now after completing its 3rd year I am experiencing a problem i.e the HDD indicator light is constantly on and my laptop slows down, the problem is so disgusting whenever I turn my laptop on for general working it starts to hung up and freeze. I am thinking the problem lies in the HDD I think which I have never replace the laptop came with genuine Windows 7 Home Basic 64-Bit and using for 1 year when Windows 8 Pro released I bought a original copy from amazon and now two years passed I am using windows 8 Pro 64-bit. Before when I received this type of problem when I format the drive it fixed but now after formatting also same problem is occurring show I do a HDD replacement please help guys. I also have a fully updated bitdefender antivirus