If the recovery CDs aren't being recognized it's possible they didn't burn correctly when you made them.
To do a Repair Install you'll need an installation disk containing the Windows 7 version currently on your machine. This Repair Install tutorial contains a link to Digital River where you can download an official ISO for your operating system. The ISO would then have to be burned to a disk or USB flash drive. A repair install should preserve your user accounts, data, system
drivers, other installed programs, etc.
Repair Install
If you prefer a clean install to remove factory bloatware and unnecessary "stuff", this tutorial explains how that can be done.
Clean Reinstall - Factory OEM Windows 7
There's one other possibility that might work for you. Your Aspire might have a hidden recovery partition on the hard drive that could restore the machine to factory specs. This Acer FAQ sheet explains more.
Acer Support: Frequently Asked Questions list for How to use Acer eRecovery