Sound recording problem

[Pjeej]

I have just reinstalled my pc and am now runnign windows xp Professional, but when i try to record something true my mic, the following problem occures.

I plug my mic in, and when i turn mic boost on, the sound that the mic registers are played back true my speakers. No problem what so ever, but when i turn the mic boost off, i don't get any sound out of my speakers what so ever. But the real problem starts when i try to record it. If i turn mic boost on, it plays true my speakers right, and then i record, and i play the recorded file, it only contains some sort of buzz. And when i turn mic boost off, it doesnt record anything

I've checked all my settings and have recorder with Audacity and windows movie maker, i never had a problem with those programs before.

I have a Asus M2N motherboard and am using the latest version of the soundmax driver that came with the cd from the motherboard.

My brother has exactly the same pc as i have, same windows and settings, and on his pc it is working fine, can anyone please tell me what i can do so i can fix this problem?