Hi there Honza_2,
Is this a secondary drive? Do you have a desktop or a laptop computer?
Anyway, I believe that it would be a really good idea to back up the data stored on the drive and do some general troubleshooting.
You can test the drive with some of these:
http://www.tomshardware.co.uk/forum/282651-32-best-diagnostic-testing-utility
See if there are abnormal values in the SMART report. You can upload a screenshot as well.
Another thing you can try is to attach the drive with different cables to another SATA port. (if desktop)
It will not hurt to update your MOBO's drivers as well.
Let me know how this goes,
D_Know_WD