Lenovo laptop shutdown suddenly after working for a while

Remove the harddrive and try turning it on. If that didn't work than try the memory and if that didn't work than your motherboard is dead. You can either buy a new laptop or get a new motherboard (it will be more cost effective to get a new computer). You can have your data move from the harddrive of your old computer to the new one if you go this route.

Sounds like an overheating problem, remove the side casing and check for fan rotation on all visible fans, most likely the cpu fan, however, the fan itself may not be faulty, check all of the cabinet for dust build up and remove, could be reducing airflow.

Sound like your power adapter is about to go. Replace it and check if will to the charging.

cooling isnt working properly

do you get any screen?
if not, something on your MB (or even the MB itself) is dead

This sounds like a overheating problem (a CPU thermal shutdown).
This is caused by a faulty fan or the heat-sink and fan is clogged with dust. Check the fan to see if it spins freely, if not replace the faulty fan. Check the fan/heatsink assembly and remove/vacuum the dust from these components.

Hello.The laptop doesn`t get hot? This is usually the problem that causes the system to crash and shut down to prevent hardware damages.

found solution on another web forum it worked.

besides downloading the driver, you need to install the software - it's titled usually thinkpad security solution.

the freeze during shutdown could be because any of these possibilities.

1. Program or TSR currently open does not close or does not release itself from memory.
2. Incompatibility, corrupt or damaged driver.
3. Temporary files.
4. Hard disk full, has errors or needs defragmentation ran on it.
5. DOS driver, configuration error or confliction in the autoexec.bat / config.sys.
6. Advanced Power Management issue
7. Virtual device driver issue.
8. Corrupt shutdown sound or issue with sound drivers.
9. Internet Explorer 4.01.
10. Norton antivirus 'Load Auto-Protect at Startup' issue.