First of all, it would seem you have a Trojan Virus. It would also seem that it is re-running itself at startup. Whatever anti-virus you are using is not getting rid of it. When your anti-virus finds it, it should include a path. Attempt to navigate to that path and delete the program manually. This b.exe if part of the Trojan Virus, the fact that there is an error may mean that the one who coded the virus was not a very good coder -.-.
But anyway try deleting the file manually/ending the process via task manager (can be opend with ctrl+shift+escape or ctrl+alt+delete -> Open Task Manager) If you don't know how to do that, go to the process tab and look for b.exe, select it and press end task (as well as Trojan.exe is you find it).
I hope that helps.
this line in the logs you provided:
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\6c153f40 (Trojan.Vundo.H) -> Quarantined and deleted successfully.
May mean that you have the "deadly" Trojan Vundo, which is Extremely hard to get rid of.