I have repaired a lot of laptops using this simple trick. The main problem with most laptops is their own heat dispassion. In time the heat sink will lose the ability to dispense the heat (mainly because the thermal compound drys out and loses the ability to transfer the heat or there is a lot of dust in the fan) . This causes a lot of problems, the laptop will overheat and shut down. Sometimes it will get so hot that the solder in the graphics control chip will melt. This causes the Black Screen Of Death. Basically this means that in the graphics chip there is a bad solder caused by heat and the laptop wont turn on(lights will come up but nothing happens). There is a chance that this bad solder can be fixed cheaply by using only a few screwdrivers and an oven. If the laptop does not work in any case you don't have anything to lose. The work can be done also with a heat gun. I have made an instructable about repairing an old desktop graphics card with this method.
Step 1: Disassembly
Disassemble the laptop. The problem is in the motherboard and it has to go to oven. So naturally you will have to take it off from the laptop. This is done simply by removing the screws from the bottom, under the keyboard and over the motherboard. Every laptop has got it's own way for this. So if yours is not the same laptop as the laptop in the picture, use Google to find a good disassembly pictures and start from there.
Remember to remove the battery first before starting and remember to ground your self so you wont do any static damage to the laptops motherboard.
After the motherboard is freed from the laptop case, remove the heat sink from it.
Step 2: Preparing the Motherboard Before Oven
After removing the heat sink. Clean everything properly from the old paste. Also clean the heat sink.
At this point put oven on and set it about to a 200'C. Do not use convection heating. Use just regular heating without the fan.
After cleaning remove the battery from the motherboard. It the battery is not removed it will explode in the oven and ruin the whole fix and possibly it will burn your house down.
Also if the processor is removable remove it too.
All the tape must be removed also. If there is yellow see through colored tape you do not have to remove it since it will withstand the heat from the oven.
Step 3: BURNNN
Now that the oven is heated to 200'C put the motherboard to the oven. Make sure it's in level so it won't slide anything off. Also make sure the motherboard is supported evenly so it won't bent.
Let the oven do its magic and after for about 10 minutes shut down the oven and open the hatch and let it cool for a good 30 minutes before touching the motherboard. This is because the solder needs time to cool properly and settle to it's own place. If the motherboard is moved while it's still hot it will brake and the fix won't work.
Step 4: Assembly and Testing
Apply a new thermal paste to the heat sink and assembly the whole laptop to a point where you can test it.
Wow. This works perfectly.
Amazing and cheap fix for any laptop in the world. If your laptop has got a removable graphics card this can be done too. Just without the motherboard. Put the graphics card only to oven.
Step 5: Finish the Assembly Properly
The tape you removed from the motherboard is not needed by any means. If you want you can put them back to their own place. I haven't done that in any case i have fixed these and not never i have needed them. And mind you i have fixed these for about 40 pieces and about 10 has been in condition that the fix won't work.
Inform me if you used this guide to fix your laptop :) Check out my other guide how to do this with a heat gun!