Avast will no longer run, gives error

on two of my machines one laptop and one desktop
avast has quit functioning, it will not even let me uninstall it at all it says Error reading product data from (program location) setup cannot continue

I can not turn on the virus shields they are all x’d out as well

funny it is happening on both machines, one is XP pro sp3, the other is windows 7

I need help as it has rendered both machines useless

thank you

Hi,
try this:

  1. Save a copy of Avast for the product you need and save it to your HDD (if not already done) :
    http://www.avast.com/download-software – all products (Free, Pro, AIS)
  2. Download the Avast Uninstall Utility http://files.avast.com/files/eng/aswclear.exe and save it to your HDD.
  3. Go to Control Panel and uninstall Avast through Add/Remove Programs if possible and reboot.
  4. If Step 3 fails, boot into Safe Mode (hit F8 repeatedly) and run the Avast Uninstall Tool. Uninstall ALL previous versions (4,5,6,7) and products of Avast you had on this machine one at a time and reboot in between each uninstall.
  5. Reboot.
  6. Install the newest version of Avast.
  7. Reboot.