my gt n7000 is getting slow, sometimes it restarts by itself and some application close by itself. i presumed the low device memory was behind all f this.i want to ask if hard reset will solve my memory problem and what will happen to my built in apps such as S-pen? will they still working or i have to reinstall it again? please i need your suggestion. thanks.
The types of problems you're describing are generally best solved by, indeed, factory resetting. If you can't find another solution, it's pretty much always the last resort. So if you're willing to do it, it's all but guaranteed to fix the problem, unless the problem is being caused by a hardware issue.
Built-in apps will all remain. Anything that shipped with the phone will still be there. Some may have updates that need to be reapplied, but you won't lose anything that was there when you first turned on your phone after buying it.