blat.exe is a process belonging to a legitimate console-based program used to send e-mails. This process can be used maliciously and has been known to be bundled with viruses such as the Backdoor.Danrit. "If unaccounted for, this process should be removed immediately. "
Non-system processes like blat.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