I am having problems doing a check disk on my external hard drive. Its a samsung 5400rpm. This is what happens when I try to bring up check disk- I tick the check boxes for "Automatically fix file system errors, and Scan for and attempt recovery of bad sectors". when I click start I get the message- "The disk check could not be performed because the disk check utility needs exclusive access to some window files on the disk. These files can be accessed only by restarting windows. Do you want to schedule this disk check to occur the next time you restart the computer? So then I click yes, and when the computer restarts it does not check this external hard drive. If anyone has had this problem before or knows how to get past this error message please tell me. Also I have another problem with this external drive, and that is when I go down the taskbar and click on "stop external hard drive" I get an error message, "the drive can not be stopped right ". Why would I get this error message, and how can I fix it ?

You show your manufacturer as windows. I don't recall windows making a computer. More correct info if you want help.