RESTRICT INTERNET ACCESS
MSN Live Family Safety - Free
Allows you to block access to websites and restrict the contacts your children can communicate with on MSN Messenger and Hotmail. You download a free program. It uses MSN Passport as gateway on the computer. It opens whenever the computer is started, and requires a login and password before granting anyone access to the internet.
Using a Parent and Child model, you can change all the settings through the MSN Live Safety website. This is also where you can monitor the computers that your Family Safety is running on.
It logs which websites your children visit. And it allows you to unblock websites that were blocked by the filter. When child finds a website they want to access, they send you a permission request. You log into your MSN Passport account, open the Safety page, and it displays all the requests. This allows you to remotely preview and unblock a website for your child.
The program cannot be closed or uninstalled without the Parent login. I think it also blocks other chat messengers.
RESTRICT INSTALLATION OF EXE FILES
I think Family Safety blocks Child account from opening any *.zip and *.exe website addresses, so it won't allow your children to download potentially harmful files. You would have to allow the website before they could download anything.
For additional computer safety, make sure your children log onto Windows using a Limited account, and not an administrator account. This will prevent them from installing any new programs which could potentially have viruses or spyware.
PRICE
Free.