You start the PC from the Acronis Emergency Disk which you can make from the ATI installed or from the CD you purchased with ATI on it in the package.
Your Emergency CD MUST be the same or later version as that you used for the backup or it is unlikely to recognise the image.
Your backup should be on an external/different drive to that you boot from. When you boot from the CD you should choose the 'Full' option as it should then provide full access to peripherals.
To make things easier for yourself the replacement system drive should be pre-formatted to that of the original (normally NTFS these days); most are at the point of purchase.
Acronis Support are correct in what they say, but seem to expect anyone using their product to have total knowledge of all functions; this is a shame as most of us don't.