Internet Connection Not Shared By My Laptop Turned Wifi Hotspot

I've set up my internet-connected laptop (Acer Aspire One with Windows 7 Starter) as wifi hotspot. The hotspot works to the extent that it lets another computer connect, but it does not provide (pass through) the internet access I have (via 3G USB modem). While searching the net for useful information I came across the recent thread No internet connection after I turned my laptop into wifi hotspot, Following up on the two tutorials mentioned in that thread, Windows 7 Tip of the Week: Use Wireless Hosted Networking to Share An Internet Connection Wirelessly | FAQ/Tip content from Paul Thurrott's SuperSite for Windows and Windows 7 Hotspot: Share Wifi With Your Laptop, I noticed that on my laptop the important Share tab is missing that can be seen in the first image in the first tutorial and also in the first image in the section "Changing Adapter Settings" in the secodn tutorial.