There are only a few things that can be done 'economically'.
1. Remove the Battery and boot only off the A/C Adapter ; bad battery
2. Try replacement RAM IF only (1) stick <and/or> swap (1) stick per boot ; bad RAM
-- Requires opening the case:
3. Disconnect the HDD and boot in to BIOS ; chances are bad HDD
4. Disconnect Battery, A/C Adapter, and disconnect CMOS Battery 10 minutes ; corrupted BIOS
IF the above fails to identify the problem replacing the MOBO, CPU or Display is cost prohibitive; new Notebook.
Unlike a Desktop, Notebook parts & labor cost exceeds on a the replacement cost.
I am having the same problem, but just got a new HDD. Is there a chance it is faulty?