hi. maybe this is called by a software. i have installed system mechanic which does such thinks on startup in schedule time even i did not understand when.or how to deactivate that,although i uninstall the aplication the tasks are stilll there. go to Administrative Tools/services and check if there is enabled a task like disk check or similar if yes stop that service.
i'd think there's something up with your C parition or main system drive do a full check disk with thorough scan to see what comes up, maybe bad sectors or something
Nothing helped to resolved the problem (probably I didn't do it right).
Anyways I think I will re-format the 2 HD's and see if that helps. I am lucky that the problem is NOT in my OS HD.