Acer stopped manufacturing scanners and providing support for them several years ago. There will certainly be no Windows 8 drivers available for any of them.
However, help may be at hand in the form of a unique scanning software product called "VueScan" which supports many makes and models of USB scanners by installing a generic scanner driver and scanning software.
Download the free trial and try it: http://www.hamrick.com/
If it works with your scanner, a serial number to keep using the software will cost you $39 (US dollars). That's very reasonable when you remember that standalone flatbed scanners are hard to find these days (you usually have to buy a scanner/printer all-in-one).