As far as I know the 1558 series was issued with several different mobo types. I own one of these laptops and I would like to buy a new motherboard for it. Are these different motherboards interchangebles, or I have to look for the same type I had. If they are which one is the better?
You can easily swap any like for like (type 1 for type 1, 2 for 2).
To make a change from 1 to 2 or 2 to 1 you need a new heatsink assembly and to go from 1 to 2, you may also need a new power adapter (a 65W adapter will power an Intel board but not one with AMD video aboard).
These seem to go for $200-250 even now -- given that the system is 6-7 years old, you may want to weigh that cost against the value of the system -- and the cost of a faster replacement system.