"if it aint broke, don't fix it?"
Might be the best advice, if the 'aged' computer in its present state as served you well, and done the things you have required.
You seem to have plenty of ram there, so a slight upgrade to the hard-drive would not go amiss, but all that would depend on whether you think its worth spending money, and would stick with the SATA drives.
Installing the O/S and drivers on a new HD, shouldn't be a problem. If you know how to reformat.