On 24 June 2011 14:30, Dennis Kioko <dmbuvi@gmail.com> wrote:
http://answers.microsoft.com/en-us/windows/forum/windows_vista-security/parental-control-time-limit-question/98543dfa-783b-4ae8-b464-c274bce895ec

http://www.google.co.ke/search?sourceid=chrome&ie=UTF-8&q=windows+user+sessions+log+in+quota#sclient=psy&hl=en&source=hp&q=windows+restrict+user+time+quota&aq=f&aqi=&aql=&oq=&pbx=1&fp=3e31eda2a50462af&biw=1366&bih=653 use Windows 7, or Windows XP or Windows Vista



Thanks for the heads up Dennis, 

From the page I found out about these two programmes that seem to do what I need

http://www.timesupkidz.com/
http://www.parentalsoftware.org/chaperone.html