I recently was given a gently used Aspire 771G and was told all I needed to do was install a new hard drive and my own copy of Windows. I went out and bought a new 500GB HD and a new copy of Windows 7. When I try to boot up the laptop to get into BIOS to change the boot settings, I receive the message that there is no bootable device detected. When I attempt to boot up the laptop with the Windows boot disk in the DVD tray, I am able to select the DVD drive to boot from. After selecting the DVD drive, I then recieve an error stating that "atapi dvd blocked by current security". I can't change the security settings in BIOS because I am unable to even access BIOS in the first place. What can I do to resolve this problem? Any help anyone out there can provide will be greatly appreciated!