as stated above, you need to find the secondary code for the real answer to what is wrong with it. All 3red lights means is that the system has had some sort of hardware failure. could be the gpu, could be the fan, could be the HDD, could be cpu, the list goes on and on.
everyone states do the xclxamp. 3 lights do the xclamp. well this is not allways the answer. 80% of the time its over heating and needs the xclamp replaced, but alot of the time 20% its something else.
so then there is the matter of openions about should I do the xclamp to prevent RROD. my openion is no, others may say yes. but I say no. Microsoft used cheap solder, high quality thermal paste and a pure aluminum heat sink. there is nothing wrong with that for say. the problem occures when the system gets real hot, it can get so hot it will warp the mobo (we are talking fractions of mm) when this happens the cpu and gpu wont bend with the mobo, therfore the crack away from the mobo, causing......ready for this???? HARDWARE FAILURE (rrod) Rhe xclamp fix applies preassure to the chips to force them back down tight against the mobo. So is the xclamp the problem???? the answer is no. the problem is heat. keep the system cool, by keeping it clean, well ventalated, and turn it off when its idle for a while. posibly add a new fan, but thats all I would recomend.