[Hyvatti]

Test the disks in another computer that has Linux - or has some windows SMART disk health monitor program. You may need to use "-s on" option before this -a option gives any information on the device. Replace "hda" or "sda" with appropriate device name, like if the disk is second disk in the system, it should be "hdb", "hdc", or "sdb".

smartctl -a /dev/hda
smartctl -d ata -a /dev/sda
smartctl -a /dev/sda

See what the general status says, and some parameters are good to check also: Reallocated_Sector_Ct should be zero for good disks, any reallocated sectors, or if the number is high and increases after self tests the disk is a suspect. Temperature_Celsius is only meaningful in the system you use the disk normally of course, below 40 the disk life is a lot longer than over 50, you can start counting months when the drive fails after that. Over 60, count days..

Then run the offline self test:

smartctl -t long /dev/sda

(Again use the device name and you may need to use -d ata too.) After an hour or so you can again query the disk status with -a and it tells in the self test log and general status how the test went. Also compare reallocated sector count with the number before the self test.

Same commands I am sure you can find in Windows in some SMART tools, but I don't know what they are.