Can I upgrade my core i5 540m in dell studio 1458 to i7 720QM?

Hello,
I want to ask if I can upgrade my i5 to i7 720qm on my dell studio 1458. I checked the SIW software and EVEREST ultimate for system slots, it showed up 2 slots "PEG slot J5C1 for *Field processor" and another slot "PEG Slot J5C1 for *dale processor" does the first slot mean the clarksfield (i7) processor? meaning that I can remove my arrandale and put the clarksfield into the *field slot? Please tell me if my Intel HM55 Chipset also needs a change. I don't want to change my motherboard so plz tell me if I can upgrade w/out changing the motherboard. The north bridge is Intel ID0044 R02 and south bridge is HM55, and cpu socket is 1156 LGA. plz tell me if any of my components needs a change to upgrade. Fan is also good, the stock version. i5 temps rise upto 75-80 under cinebench load. So please tell me the cost of i7 from dell and if any component needs change. Thanks.

I'm not sure if you can upgrade the CPU, but if you can, and you are currently only using onboard graphics, the fastest chip you could install would be the Core i7 620M, the Core i7 700QM, 800QM and 900XM series do not have integrated graphics. You wouldn't see much of an improvement over the Core i5 540M if you upgraded it to the Core i7 620M anyway.

if i get it upgraded from dell itself (i7 720qm), will it do the trick?

If you can get Dell to perform that upgrade for you then great but i don't think that they will do that and if they did, it would likely be expensive.
I7 will support that chipset but it must have a graphics card(integrated or dedicated). your 540 has integrated graphics already on it and the 720 and the other mobile quad cores do not have integrated graphics. There must be a graphics chip for a modern computer to run.
Take a look at your laptops product page( http://www.dell.com/us/en/home/not [...] s=19&s=dhs ) and notice how the quad core requires a graphics card to be added since the processor does not have graphics onboard.
I'm gonna stay with my old suggestion and tell you to just keep what you have or buy a new laptop with the 720.

Well that would have been useful information. It should work so you can go ahead and try it. I still don't recommend it though because of the difficulty and how easy it is to damage a laptop while taking it apart. Good luck