sorry, couldnt read your private message properly cos of the formatting on the N900. i also tried the headset in a pc and it worked fine. just not in phone. a normal earphones worked in the phone.

the problem is because the nokia headset has four connectors that the phone expects to detect whereas normal earphones just have two (look at the plug to see what i mean) it seems like one of the wires connecting this breaks stopping the N900 from detecting it.

i searched this site and found a few bug reports about this all resolved as it is the hardware, not software.

i was able to go back to carphone warehouse because i hadnt had the phone for long. i did say that it was the first time i had tried them and they tried a new set which worked fine. i dont know how much luck you would have with this as you have had the phone for a while.