format the whole computer install a nice security sute ...dont install unknown softwares or softwares that comes in with other softwares as bundle.....try to check the processes daily and if u check any suspicious services or processes end the process there only and remove that from startup processes.....try to clear temp folder....go to run type "%temp%" and delete all..it contains temporary files that are needed in installation of softwares....keep ur windows defender on
if u need any help contact me ... i am there