Computer freezes/overheats (15 pics)

How to Fix an Overhmy computer overheats, i guess after some time of playing CSS. CPU get to around 46 *C and my computer just freeze. The cpu fan came with my cpu so it was never changed and could this be cousing the problem ? or is it power supplyer ? iam realy getting annoyed and worried because iam thinking to upgrade my video card soon and it would be realy disapointing if i wouldnt be able to use it for games. If it is CPU fan can u recomend me new one?