ybrowser.exe is a process from Yahoo! which offers additional functions to Internet Explorer. "This program is a non-essential system process, and is installed for ease of use. "
Non-system processes like ybrowser.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that over time your registry suffers fragmentation and accumulates invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues