Can you boot the system, or do you need this because of a problem?
Are you running windows 7? If yes and you can boot the system, just make your own recovery disk. Go to control panel and select back up, the make an image file of your C drive. NOTE this is even better than the acer recovery disk as it will also restore all of the programs you installed!!
If you can not boot the laptop, options are limited. (1) Go to Acer and purchase a new recovery disk. (2) can try, barrow a Windows installation disk, do a clean install (Do not insert Key). After installation, inset YOUR acer Key and try to activate. If it tells you to call Microsoft, do so and explain that you have a valid key for that system but lost the recovery disk (3) Buy a copy of windows 7