Is it possible you missed the prompt to insert the other disk in the Upgrade Kit? You can try that now if this is the typical Acer Upgrade kit with Acer customizations on one disk and standard bootable Windows 7 installation DVD on another.
If not and it didn't/doesn't offer to Roll Back the failed in-place Upgrade then it may be lost. I'm sure it gave you plenty of warning that all data must be backed up any time you do any
install or repair of Windows.
But MS requires OEM computer makers to provide bootable Windows 7 installation media in the Upgrade package which can also be used to get a superior Clean Install of Windows 7 without the OEM bloatware and useless factory utilties which have better versions built into Windows 7. You can do that now following these steps: Clean Install Windows 7.
With the Windows 7 Product Key which should also be provided, MS will activate it in their Servers and protect your right to clean reinstall no matter what Acer tells you. We can help you do this since we are the top site on the web for this.
If you want to try to repair the extant installation then you can boot into the installation DVD System Recovery Options
, see if it finds an installation to Repair, or click through and run Startup Repair
repeatedly to see if it will start and/or make your log-in screen functional. You can also try Acer's abysmal Tech Support for the purchase.
If you have files to copy out to external HD or flash stick with the same DVD Repair console use this method: Copy & Paste - in Windows Recovery Console.
or use free Paragon rescue disk to recover data
If there are any problems with booting the installer check that you have the required Windows 7 Product Key and we will provide you with the licensed version official Windows 7 installer with SP1 ISO to burn to DVD or write to flash stick. How to Boot your Computer from a Bootable CD or DVD