Hello,
Yes, I would consider the hard drive to be a potential suspect.
However, with the freezing and crash issues, I would check for over-heating.
You should also check the RAM, and make sure ALL fans are clean and running properly.
If the CPU or power supply fans are bad, I would replace at least the CPU.
Depending on how hot it gets inside the case, if the power supply fan goes, everything else can get very hot.
I would go so far as to remove and reseat the RAM modules.
I agree with running scandisk in thurough mode to check for bad sectors on the drive.
Shut down EVERYTHING, including screen savers first. (use Alt-Ctrl-Del)
If the fans are fine, and the drive passes scandisk, I would go ahead and format and re-install the OS and software.
Listen carefully for any unusual noise from the hard drive while installing Windows.
If you hear grinding, or see excessive drive access times, the drive is no longer reliable.
Chas