I have installed my samsung galaxy tab 8.0 3G 3 (SM-T311) via OTA kitkat android version. but after I install new problems arise that make me upset. Sensitive Touch screen is not working properly, the device works very slowly, the display device is not in line with expectations. really makes me upset and confusion.

some of the things I have done but did not produce results at all:
- I did flash using Odin 3:09 with the existing firmware in http://www.sammobile.com/firmwares/
I started by doing a re-flash firmware version 4.4.2 the problem is not solved, I went on to re-flash the 4.2.2 version of the problem is not resolved well. Odin fails to re-flash my device with the caption FAIL!

so while I was stuck in this state
please help me in solving this problem, what steps should I do? to be able to restore my device performance as before.

I'm sorry if my english is not good: D