The group policy client service failed the sign in access denied

You can try performing a System Restore from Windows Recovery Environment (if you have not done this already). To do this, you can follow the steps below:
1. Insert your Windows disc and then, restart the computer.
2. Press any key when you receive the message "Press any key to boot from CD or DVD"
3. Set your preferences for Language to install, Time and currency format, and Keyboard or input method. Click "Next".
4. Click "Repair your computer" and select the operating system you want to repair. Click "Next".
5. Click "System Restore" and click "Next". Click a suitable restore point and click "Next".
6. Confirm the disk you wish to restore and click "Next".
7. Click "Finish" and then, click "Yes".
8. After the process is complete, click "Restart" to restart your computer.
9. Once the computer restarts, click "Close" to confirm that the System Restore was successful.

Now, see if you are able to sign-in. The following link can be helpful:
http://answers.microsoft.com/en-us/windows/forum/windows_vista-security/the-group-policy-client-service-failed-the-logon/6b069a74-8524-442c-8ff1-d723e2a4e992

In this case, it is recommended to contact Acer technical support for further assistance. To do this, the following link can be useful:
http://us.acer.com/ac/en/US/content/service-contact