Yes, it could be the HDD, but it could be also the RAM or the processor, so you need to check some things.
Firstly, if you have the option, try the RAM stick on another laptop.
Secondly, you have to be sure that the laptop fan is spinning correctly and the CPU and the GPU are properly cooled down.
The third thing is the HDD. If you have an external case or SATA-USB cable, you could pull out the drive and connect it to another PC. If the drive shows the same error there, you could make a scan with the drive manufacturer's diagnostic tool for S.M.A.R.T. errors.