Re: Phone won't turn on
What device do you have? That's the only way to know if you can take the battery out. Meanwhile, It won't turn off again, or you can't see any display to know you are turning the device off? If you continuously hold the power button the device should turn off, like you would force a PC to do. If your device has a battery that is not removable you can hold the up volume button while powering down to simulate a battery pull. Some devices with removable batteries allow this same procedure to simulate a battery pull, however we would need to know what device you have to know if this is the case.
As for your freezing issue it sounds like you are being extended on resources and your device cannot keep up. The way to reduce or limit the strain on the memory being used is to do one or all of the following; Clear caches on the device, delete or move to archive SMS and MMS messages that are no longer needed, delete or remove items from your email such as drafts, sent mail, and saved mail. The big 3 for cache removal are Facebook, SMS, and email, any apps outside of those can only help but those will be the main ones. Also turning off "FastBoot" will help at start up by limiting the number of items that are started when the device turns on. I would also look at any recent apps that have been installed. Read the reviews of the app and see if others are having similar issues and then try to find an alternative app. Read the 1 and 2 star reviews those will be the ones that will tell you the most about whether an app has issues. Additionally do not install battery saver apps or memory booster apps. These will often cause more problems than they are worth, consuming battery power and over working your processor.
Post back what device you have and OS you are running and more help may be available to you.