go to settings, then to about.
the version is there should be 3.2.1 i think (i dont have my tab with me but its in the settings)
but you probably have to do another reset if your having issues
did you add a new or different sd card or anything else?
back up any data that you need 1st
on the next reset be sure to choose wipe data or similar, i forget exact name, but you can look in the manual or search the best method to do the reset completely. sometimes if it does not do it right you have to do it again.
also be sure to test it with no apps but only stock apps, if those are ok then add one app and fully test it for a day, then add another app and test again.
keep track of what apps you install cuz it could be an app causing the issues, if not its a hardware issue if several resets do not fix it.
let us know how you made out and if it was an app issue which one.