about my android OS

We'll need more information before we can help: what error messages do you see, for example. A detailed description of what's happening will help us identify the cause.

If the problem is a corrupted OS (i.e. if the phone won't boot - apps crashing is probably something else) then how to reload depends on what device you have. So you'll need to tell us that as well.

As a guest you can't respond to this. So you can either post a new question, including as much information as you can, or else you could register (it's free) and reply to this.

Good luck