Hi all, I was trying to fix my friends laptop as she said it was very slow (well that was an understatement). The Antivirus was out of date and with the computer being so slow, I took the hard drive out to attach to my computer to scan with AVG and Malwarebytes, hoping it would speed it up a bit. After running these scans I also did a Disk cleanup, error checking and disk defrag while still connected to my computer. When I put in the hard drive, i get an error message saying no operating system black screen. When I go into the BIOS the hard drive is not listed. There is no option in the BIOS to auto-detect hard drives. The operating system is definitely on the hard drive as I have checked. Has anyone ever had this problem after taking out a hard drive, as now my friends computer is not working at all. Thanks in advance.