[strike]Many systems running a single jack for headset/mic use TRRS.
Now TRRS has one extra ring than a normal jack and may require an adapter. This extra ring is what is used for a mic.
Please confirm with the system maker before getting an adapter, if it is a TRRS setup the adapters are easy to find because every cellular phone in the world uses them.
If you have a cell headset you can try it on the laptop to see if it works as well since most are trrs.
This is a generic Google link. but gives you an idea of the adapters, they are passive and can be made yourself with just a few parts if needed.
http://www.ebay.com/sch/i.html?_sacat=0&_nkw=trrs+female+to+trs+male[/strike]
Edit, scratch that, it looks like you HAVE the TRRS adapter.
I thought you tried a buddy's header
Please confirm with your notebook maker that the unit does in fact use a TRRS jack, if not you may want to look at a usb soundcard with headset/mic jacks on it.
Any chance to see the Sound -> Recording section to see what it shows when just the mic is attached?