YLoD is caused by overheating. Games could be a part of it but probably not.
Maybe having a crappy air flow and playing on the console too much can heat the motherboard and make the joints around the CPU & GPU dry out.
All you need to do is get a heatgun and heat up the parts around the CPU & GPU and apply some thermal paste (non silicone based) and put your ps3 back together and it should be fixed. There are plenty of tutorials, but there are more people claiming they can fix it for £50+ just to do that method....
Lew.