How to make my laptop a WiFi Hotspot (using internet from USB 3G device)

You couldn't do it before Windows 7... because no previous version of Windows included the Virtual WiFi components. So, if you want to do this with XP or Vista, forget about it.

Now. If you do have Windows 7, you can use Virtual Router. It's still in Beta, so it's Free. You could also try Connectify, and see if the limited lite version fits your needs , or you can use the MyRouter.

You can create an ad-hoc wireless network on your laptop, and then share USB 3G modem internet connection with this ad-hoc network so that every device which will connect to the ad-hoc network will have an Internet access.

How to Share Internet Connection with Ad Hoc Network on Windows 7

With some chinese cheap modems I got BSODs several times after an hour of work.

Hope this helps.

On your laptop connected to local connection: open cmd and run the following commands

netsh wlan set hostednetwork mode=allow ssid=name_of_network key=password
netsh wlan start hostednetwork

then active the sharing of this local connection to this new created miniport wifi connection.

On your Android cell, active wifi features, then select the name_of_network and fill in the password.

If other connections instead of local connection, shared the internet from it to the miniport wifi connection.