Problem
The setup program indicated wrongly that Microsoft Access is not installed.
Cause
The setup program is opened with Avast Antivirus in a so called "Sandbox".
Solution
When Avast indicates that the program may be unsafe, then select "Open normaly".
(http://www.itman-nv.com/uploads/sandbox.png)
The Sandbox can be disabled as follows:
1) Open the Avast interface by dubble clicking on the icon in the Windows toolbar
2) Click at "ADDITIONAL PROTECTION" on "AutoSandbox"
3) Click on "Settings"
4) Remove the check mark at "Enable AutoSandbox"