first of all i brought this phone just a week ago and rooted the phone the next day .
u believe me or not rooted phone rockz.
micromax a57 has many rubbish apps like mbuddy, mstore, whatsapp(old version . update needs 6 mb on internal which is costly on 128mb free memory. ) then Hookup is good but when u use hooup with messages it doubles notification and due to it your phone hangs.
once you root your phone . you can install link2sd , titanuim backup which helps in freezing many system unwanted apps which you are fed off ,
Try swapper to increase ram . man believe me phone works in go .
Before root: my phone has problems llike music player pauses when out of memory, phone hanging when a call comes during i use facebook etc.
After root : 75 % of my phones problem solved.
so i suggest you to rot your phone carefully with a keen mind. see youtube videos ask help here. no worries we are to help you.
Now if you are not ready to root your phone then install advanced taskkiller pro. which is paid version available in play store or get from torrentz. if you need ask me i will help with link.
Any furhter doubt feel freee to ask here MICROMAX NINJA a57 facebook group
Or subcribe me and message me Akhil s naik
if you dont subscibe and messaged me then your messages go unnotified for me.
Always ready to help.
Akhil S Naik