My Toshiba Satellite L305D-S5923 has just started misbehaving some few days ago. In the middle of a work it could be anything the screen can just go off without the machine shutting off. When screen goes black and the machine freezes. Sometimes it gets so bad that holding the power bottom down for like 30secs does not even turn it off. Then it means i have remove the battery to start everything all over again. I am on windows 7. Anyone experiencing this problem too? Have you got any suggestion or solution for me?
I have tried using a monitor but still it did not help.

shut down the system, unplug it, take the battery out and press ON button for 20 seconds, then realise the finger and wait another minute,the light bulb of th screen probably needs to be replaced.

If the system is freezing as well as the screen going black, then it may be that the battery needs replacing. (I have seen this occur before).
One way of checking this would be to remove the battery and then plug in the mains lead without the battery installed. If it runs ok, then it is a faulty battery that is causing the problem