Problem With psexec (Solution)

I do my pentests on a Windows XP sp3 box and I had this problem, that I could not get psexec to work as I kept getting this error message.

[*] Started reverse handler on :4444
[*] Connecting to the server...
[*] Authenticating to :445|WORKGRO[*] Started reverse handler on 192.168.56.3:4444
[*] Connecting to the server...
[*] Authenticating to :445|WORKGROUP as user ''...

[-] FAILED! The remote host has only provided us with Guest privileges. Please make sure that the correct username and password have been provided. Windows XP systems that are not part of a domain will only provide Guest privileges to network logins by default.

[*] Exploit completed, but no session was created.UP as user ''...

[-] FAILED! The remote host has only provided us with Guest privileges. Please make sure that the correct username and password have been provided. Windows XP systems that are not part of a domain will only provide Guest privileges to network logins by default.

[*] Exploit completed, but no session was created.

That was because if your Windows XP Professional based computer is not in a domain, by default all users trying to log in to it over the network, are forced to use the Gust Account. To find out more information go to http://www.windowsnetworking.com/articles_tutorials/wxpsimsh.html

So the solution is to

Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
And change the ForceGuest value to 0

Done!