Hi,
Most likely the cause of the overheating is the fan its not running properly though you may hear the fan is running but its not working as it used to, also I suggest try to check where is heat coming out from if its on the Hard drive bay, Memory bay or the CPU area, try to fell also the air vent if you feel coming out from it.
You can try this steps and see if it fix your issue.
1. Follow this link to download Speedfan:
http://www.almico.com/speedfan443.exe2. Open and install Speedfan.
3. Launch Speedfan (this usually takes at least a minute to start).
4. Observe the temperature readings you receive. If your temperature readings are above 60 degrees Celsius or higher, especially when the computer is idling, then your laptop is running too hot. If your laptop temperature is below 60 Celsius, then leave Speedfan running and check on it periodically to see if the laptop is heating up (whether idling or in use).
If you are sure your laptop is overheating, then there are a few stopgap measures that you can employ:
1. Place the laptop on top of a cookie sheet.
2. Place laptop on edge of table so that the air vents on the bottom of the laptop are not being blocked.
3. Use a standing fan and turn it directly on the laptop.
Ways to fix laptop from overheating:
Follow this link for pictures and text explaining the next several steps.
http://www.insidemylaptop.com/disassemble-acer-aspire-5610z-laptop/ (The laptop model used in these pictures isn't exactly the same as yours but it should be close. Don't worry, this process isn't that difficult, and you won't have to go any farther than removing the cooling fan.)
1. Turn off laptop, unplug laptop, and remove the battery.
2. Unscrew all panels on the back of the laptop.
3. Remove RAM, Hard drive, and cooling fan by following steps 1-8 on the linked website. Skip removing the DVD drive (step 6).
4. Using compressed air, a vacuum cleaner, or an air pump, blow air into the now open compartments in the back of the laptop.
5. Blow out the dust and dirt in the cooling fan.
6. Reassemble and turn on laptop.
7. Run Speedfan and monitor your temperature.
If your laptop is still running hot, then either employ the stopgap measures or take the laptop to a laptop technician. The laptop technician can take your laptop completely apart, reapply thermal grease to the CPU heatsink, and blow out more dust and dirt.
Good luck, thanks for using FixYa, and please post back to this solution if you have any difficulties.