Yikes, this answer comes from another forum and has solved this issue, if you feel comfortable working in the Registry you might want to give this a go.
This problem may be also caused by the policies keys. You can use the followling method to remove the policies keys:
Remove Group Policy
================
1. Click Start, type REGEDIT in the Start Search bar and press Enter.
2. Locate the following key in the left pane:
[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft]
3. Highlight “Microsoft” folder and click "Delete".
4. Repeat to delete the following keys:
[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies
[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Group Policy]
[HKEY_CURRENT_USER\Software\Policies\Microsoft]
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Group Policy]
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
If some keys do not exist, please ignore them.
If the issue persists, you can run an in-place upgrade to repair the system.
In-place Upgrade
=============
1. Insert the Windows 7 DVD in the computer's DVD drive.
2. Click Start and choose Computer.
3. Please find the "setup.exe" file in the DVD-ROM and double click it.
4. Click Install now.
5. When we are prompted to input the product key, please click Next without inputting any key. The setup wizard will prompt and ask if you agree to install Windows Vista without the key. Please choose to confirm.
6. When you reach the "Which type of installation do you want" screen, click Upgrade to upgrade the system files of Windows 7.