Am trying to boot up an Acer Aspire 5253 series laptop and keep getting 'A disk error occurred. Press ctrl + alt + del to resttart.' In an endless loop. Tried to boot to Windows 7 repair disk, but get an os file not present error message. Have reconfigured BIOS every way I can think and still getting nowhere. Can anybody help? I am a midlevel operator who is ver good at following detailed instructions even though I understand only basic technical aspects of computer operation. Please be gentle.