Q: I noticed freezing of the application after short period of working that can't open since installing another one

i don't get. can give examples?

which apps?                   

Close All Open Apps...  Perform a Reset... Try again...

Reset  ( No Data will be Lost )

Press and hold the Sleep/Wake button and the Home button at the same time for at least ten seconds, until the Apple logo appears. Release the Buttons.

http://support.apple.com/kb/ht1430

Also, See Here...

Troubleshooting applications purchased from the App Store

http://support.apple.com/kb/HT4211

Try this, if it does not help go to settings>general>reset>reset all settings and no this will not erese any information.