First, I'd try to download the drivers again. I'm guessing that your download was corrupted or never finished...the download/installation worked for me a few minutes ago. For the Driver/Software download page, click here.
If that doesn't work, you may have a Program Recovery option available from the start menu. If the option is available, it should walk you through the quick process. Just use it to reinstall ATI's software and drivers.
Finally, find your System Recovery disk (should have either come with the laptop, or possibly burned by you). Open ''my computer,'' right-click the drive containing the CD/DVD, and select ''explore.'' Then look for a folder (or subfolder) titled ''ATI.'' There should be an EXE file you can reinstall it from.
Hope this helps,