Yes, you are right. Computers very often slow down due to the gradually decreasing performance of their hard drive. And if you hear these “crunching” sounds, you need to replace the hard drive until it breaks completely. By the way, disassemble the case and make sure that the sounds appear because of hard drive, it can also be the problem of cooling fans.
The most important thing you should do right now is backup! It is important to copy files and any other documents to the external drive. Otherwise, you will have to change the hard drive and worry about data restoration (and possibly pay a lot of money for recovery). And in general, take it a rule to regularly make a backup copy of any important data you store on your computer.
How to check the hard drive:
To get started, use the standard utility you can find in Windows OS: go to “My Computer”, find the necessary drive and right-click it. Then select “Properties” and go to the “Tools” tab to start the disk check.
After that check the manufacturer of your hard disk and on its official website download the program for testing (they exist for almost all manufacturers). Or you may use a universal program that fits all drives, for example - HDD Scan or Viktoria HDD.
How to replace the hard drive in your computer:
It's simple - shut down your computer, remove the side cover and remove two wires from the current hard disk drive.

Then unscrew the screws on which it rests (in modern cases there can be latches instead of screws). We take out the old HDD and insert a new one instead. And do the same things in the reverse order - fasten it, connect the wires and close the case. That's it. A more complicated task is to install the system and copy the data to the new hard drive, but it’s a topic for one more article.
If you have any further questions, please do not hesitate to contact our help desk!