[#0005ff]You don't download it - it's a command which is already available in Windows. Go Start to tRun and in the open box, type chkdsk /r and hit Enter. A message will appear saying the task cannot be carried out now and asking if you want it to run at the next restart. Accept that offer and restart the machine.
The switch after chkdsk is /f if working within Windows but changes to /r if it runs in a DOS environment before Windows loads and it has a better chances of fixing any disk errors it finds. You could also have run the same disk check in Windows Explorer but doing it the way I suggest above is the better option. [/#000ff]