winstart.exe is a process from iGetNet.
It usually installs components without your knowledge and turns the Internet Explorer address bar into a keyword engine piped into iGetNet. This process should be removed to ensure your personal privacy.
Non-system processes like winstart.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that your registry has suffered fragmentation and accumulated invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues.
Multiple copies of a process in your task manager may indicate the presence of a virus or Trojan. Make sure you always use an updated antivirus software and perform a full scan to identify any such cases.