If it is still covered by a warranty, I strongly advise that you let the service center handle the case to make sure of technical assistance you needed even if they have replaced your cooling system. The fact that the problem recurred, the technical solution provided was not addressed. This could be a manufacturer's defect which was not monitored since you only used your computer for three months. This is the best approach to your problem if your unit is still under warranty.
Otherwise, you consider the following, but still advise technician to do the job for you if you do not have the technical knowledge:
1. Check the air vents.
a. Check the vents to see if it is dusty. Dust blocks passage causing heat increase
b. Shutdown your unit;
c. Disconnect the power cord from the electrical outlet.
d. Remove battery per instruction from its service manual.
e. Remove the dust from sanding. The blower is highly advised. Do not use mouth.
2. If (1) did not address the problem, update system BIOS; The BIOS can be a source of heat if the temperature is outdated;
Installing Drivers or BIOS from.
a. Turn on the laptop and make sure it's connected to the electrical outlet
b. The battery must be at least 15% charged.
c. Remove all the external peripherals.
d. The laptop should be free from any works.
e. Enter your Service Tag onto the site to get the needed data from your BIOS. Check here
Your Service Tag is on a bar-coded white label on your computer or peripherals, which is a unique 5-digit or 7-digit alphanumeric, composed of letter and number code. Its numeric conversion is an Express Service Code.
f. Install the system BIOS from the given site. See the figure below.
3. Activate diagnostics test on system fan to examine its status. You can also check the CD that was given to you when you bought the computer. This CD has file of drivers and utilities that you can use for the same purpose via off line. The following are the steps to do this:
a. Insert Recovery CD;
b. Shut the computer down
c. Turn it on
d. Press F12 repeatedly when logo appears
e. Enter the option CD/DVD/CD-RW in the boot device list,
f. Enter the CD-ROM as seen in the menu to boot
g. Enter the ‘Press any key to boot from the CD after it appears
h. Follow the prompt after choosing in the menu Select Custom Test System Fan
The link here
will guide in the procedure in running custom test on system fan.
You can also diagnose via online using the link here
If the test fails, refer to a technician for the examination of the system fan.