how to free unused memory in android? i had downloaded an app but after connecting my phone(HTC ChaCha) to pc and after disconnecting my phone from pc,i found that the app is not working any longer.Rather the phone was failing to recognise the app.So i uninstalled it.But after uninstallation the memory occupied by the app was not freed.how can i free that memory?
In settings, see if you can find something called "Application manager". When in that, find the "all" list. See if the deleted app is still listed there. If yes, there should be a few options to clear the data it stores, use them. I am not sure how your android looks like, but they should generally be the same.

If that does not help, you can use this app: Clean master - https://play.google.com/store/apps/details?id=com.cleanmaster.mguard&amp;hl=eng

I use it on my private phone, and it seems to do good when it comes to free up memory. However, I am unsure if it work on your phone, as it does not list all versions it supports. It's also free.

You can also connect the phone to your computer again and see if you can remove the app data manually, however, how this can be done differ between phone models, and it can be risky as the data you want to delete might not be found so easily.