This file is a harmful and undesirable program. Probably virus. It's recommended to delete it.
What is rb.exe Windows startup process
File name: rb.exe
Program name: RamBooster2
Description: AKAK TROJAN
Information added by: Peverall at 29 September 2008
Hint: If rb.exe file is a virus or trojan, we recommend to use a antivirus software or registry cleaner.
We are presenting list of Windows processes, startup files.
Name of rb.exe is RamBooster2. Some of them are viruses, so you should use a antivirus program.