My Samsung duos is not working properly and it has gone very slow. Earlier I used to have no problems but now when i start typing my messages it works very slowly and and i have to wait for the mobile to respond this problem is on both on calls as well as on message. Please suggest what to do?

That is very common problem with almost all mid-range , budget Android phones. Best solution is to avoid unwanted application, uninstall whatever you don't need. If that is not solving problem then you may consider reset to factory settings. It will delete all data and will make your phone like new.

One more thing, if there is any update available from Samsung for your phone, then try it as usually they comes with more speed and enhancements.

Thank you, I formatted my device and reinstalled only those apps which were needed.

Welcome, glad it helped you. So going to continue using this phone or planning to buy new ?

I hate Samsung phones.... Will suggest you to go for the Windows phone, best seller is Nokia which is Microsoft now..