LoopG

bool timerstate = false;
int lapse = clock();

if (cb1->Checked == true)
{
   timerstate = true;
   while(timerstate == true)
      {
         if(clock() - lapse > 5000)// u said int lapse = clock(); -> amount of lapse - amount of clock() = 0
            {                      // 0 cant be bigger than 5000
                 //memory code ect..
                 lapse = clock();
             }
        }
 }
else
{
      timerstate = false;
}