Mostly this is a true statement. However, hard drives can drastically slow down sometimes as they fail. They can run out of set-aside sectors that are used to substitute for bad sectors, at which point they then are forced to retry reading/writing failing sectors that can no longer be replaced.
This can drastically slow down computer performance, and unfortunately, such slow downs are often the only symptom of a dying hard drive before it completely quits working. This slowing down can occur quite quickly or it can take weeks.
One way to tell if it is happening is if there are periodic and abrupt temporary stoppages at the same time the drive activity light goes on solidly. The worst version of this situation in Windows is if a failing sector occurs in one of the registry files.
In the typical slow system that just needs an OS reinstall, because the disk is rewritten, it going to give you hint if their an underlying hard disk issue...
Many times when I do an OS reload if the customer has never done it before and it had an older small hd I will recommend the customer do a disk upgrade. The reason I do that with drives get cheaper better faster and higher capacity is it a good upgrade...
Plus... I NOT DO CUSTOMER BACK UP ! and I will not touch a customers system till the customer signs off off that they have backed up what they want...backup is always a customer responsibility...I walk you throught it but you got to do it... reason I can replace anything but customer data (old FE saying "customer data is sacred")...when you touch a system anything can happen... (once did an on site and had a business system drive blow up just turning the system off
So the nice thing is.. customer never really have a complete back up ever when they say they have and turn it over for repair..
So if I replace the hd I will set up the new hd put the old hd as a 2 hd but uncabled
Then let the customer use and check out the new system for a few weeks..
That way if the customer stated they are missing a file it's quick and easy to cable up the old drive and find the file..
And after the customer is happy they have all their files on the new disk the old disk gets a format and become extra storage in the system...
FYI to you folk's that work on friends computer ... you want to loose a friend fast .. have them think you lost their data even just that one picture they really deleted by mistake before you ever touched their system..