Hi, its running a programe called checkdisk to scan the hard drive for errors. let it run to see what it finds, you can also run it by going to my computer , right click on any drive & select properties. click on the tools tab in the window that opens & click check now, make sure you tick the boxes that say automatically fix file system errors & scan for & attempt recovery of bad sectors. let it run & any problems it finds should be fixed & with any luck wont bother you again at start up.