Use "IMGBurn" to create a CD from the SeaTools ISO file, then boot your problem PC with it & SeaTools will eventually open. Tick the drive to be tested, then click "Basic Tests" and choose "Short test". If the drive passes that test, double-check by using the more thorough "Long test".
If either test says "failed" you need a new hard drive.
Note: you can test any brand of drive with SeaTools, not just Seagate/Maxtor drives.