Black Candles are bearish lines in candlestick and candlevolume charts. They signify that the closing is lower than opening for that time period.
CHKDSK, short for Check Disk, is a utility that checks the integrity of the files and file structure of your hard disk. I'll walk you through it. I have disk problems and you said I should run CHKDSK. Great.
A computer running Chkdsk during startup is probably not causing harm, but it could still be cause for alarm. This command-line utility also called Check Disk checks for and fixes file system issues on hard disk drives.