A full reinstall may be premature. The process of locating the cause(s) of the issue can be complex, but it could be as simple as isolating a bad startup item in your User account. Diagnostics is part art and part science, but it's rarely appropriate to jump into major surgery (full erase/reinstall) prior to doing some diagnostic tests. (How different would the fable of Androcles and the Lion have been if Androcles had amputated the lion's paw, rather than remove the offending thorn?)
First, start up your system in Safe Boot.
https://support.apple.com/HT201262 If the issue continues, create a new Administrative User account (Test User)
https://support.apple.com/HT204443 to see if the issue persists in that new, "clean" user account. If either of those eliminates the problem, then a reinstall of your system likely won't be necessary.
Also, run Disk Utility > Verify Disk.
https://support.apple.com/kb/PH20570 If no problems are found, a complete erase/reinstall of the hard drive is not likely to be the answer, either. If problems are found, you may only need to run Repair Disk.