iPhone 4 - screen locked on recently called list

[chaitu49]

I have an iphone 4 which was working fine until a few hours ago. My home button hasn't been great for a while and I use assistive touch. Around 2 hours ago, the screen is locked on the recently called list. The lock button on top locks the phone but does not turn it off. The home button on assistive touch does not work. I can increase/decrease volume, just can't get the home button to work or the phone to turn off.

I am going nuts. Please help!

(I am currently trying to drive down the battery to zero so that I can recharge it...)

Thanks,

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I did update the iphone 4 today (a few hours ago). Since then the iphone would not turn the screen off when I take calls... Weird!

Please help!
(iPhone is still stuck)