The file hpbq138.exe is a legitimate file provided by Hewlett-Packard (HP). It is not a malware or virus. However, as with any executable file, there is a risk of it being exploited by malware or viruses if the file is modified or replaced.
If you no longer use an HP printer or need to remove the file for some reason, you can uninstall the HP printer software. To do this: hpbq138.exe