Whats this SMD Component?

Hi,
Im looking at a mainboard for a lenovo z530 laptop. It doesn't boot up or start up the display.
Ive identified a burnt component on the back of the mainboard. Its discolored and has burnt a hole in the sticky plastic shield that goes above it. I figure its a part of some of the power supplies on the mainbaord as it is next to the CPU and the burnt component seems to be on the opposite side of the board as the inductors which are the R36W 4C type. The components I need help with are the ones in the yellow square, They are 4 pin devices with a metal cover/can on them, I was guessing earlier that they may be DC DC converters or opto couplers, oscillator but I am unsure. Any help would be greatly appreciated. also i cant find a troubleshooting guide or anything like that for the laptop,its pretty limited support wise. I do have the service manual but that more or less only covers; dis assembly etc. I figured if im gonna have to replace the mobo i might as well try and fix any obvious problems
The components have a symbol on them like IYR but the y is more like a pcb symbol for an antenna, the larger of the components seems to have numbers on them 6725 9327 1132 which in google turns up nothing.

 

Hi steve,
thanks for the reply, I wonder is there any way i could test them in the board, I have a dmm now, but maybe it would be better if removed one of the identical small ones and have my friend test it with his peak component analyzer in the morning when i see him. Yeah the one that got hot is what has me suspect of the laptops failure and refusal to start up.
Also when you say theres too amny leads on one of them are you referring to the toasted component? Ive looked closer and it does look there are pins down the long side on the component but there actually aren't.

 

Hi steve,
The larger of the components has this series of numbers written on both of them: 6725 9327 1132 whereas the smaller reads 6721 8812 1130. googling that turns up nothing for me even with keywords. theres a symbol on allof them like IYR and what might be a logo, the logo looks like a circle with two lines through it stamped on it. Ive drawn an image in paint of what it looks like.
There's a location on the PCB elsewhere where its not populated by these two types of component but they are beside another pair of them. The larger component has four pads/leads around the outside corners and three underneath it, where they cant be seen. ive attempted to illustrate this in paint also. the smaller of the components has six pins/pads, four around the outside and two underneath the component,

 

Hi Dave,
Looks like a mosfet by IR alright they have a product called directfet. Thanks for your help. I wonder how would i identify it now. They all seem to have part numbers whereas i have a series of numbers.

I've searched and they seem to be the 6721 and 6725 series. A google of ir 6721 and ir 6725 shows them up. I think the other eight digits are lot numbers but i emailed IR anyway. Will report back with findings. Thanks steve and Dave