Yes, we can. W8968 has wireless router mode. You can connect the LAN cable to LAN/WAN port of W8968 and configure it in wireless router mode.

Is there any anti-virus software running on those three laptops? When the printer is connected to them directly, you can printer, right? The driver of printer has been installed properly?

Contact your retailer and replace it under warranty.

If you bought it in Italy, I don't think you can get a replacement in Bangladesh as their products have no internation warranty... You have replace it where you bought it from...

I don't think so... Your main router has no access control feature?

How about status of all lights on the range extender when Wi-Fi connection lost? At that time, if you connect to the main router's Wi-Fi directly, can you access internet? How does it work again...