I have that problem, but I cannot fixed, and my warranty was, well, null, since I got it in a popular market (San Juan de Dios, in Guadalajara). I have to buy another, now I have a Platinum one. I don't know, but I have the feeling that all beging whe I left the GC turned on with AC playing during about half hour (also, there was a floral adornment hanging above the system, and it fell down, so I belive that also have something to do with it). My firts GC frozen only two times (with Sonic 2 and THPS 3, and also I scrached my MX Superfly disk and every time it went back to the game select screen, it frozed with that dawn buzzing sound).