sounds like the Commands menu has been removed from his popups.

Alt-R click Popups tab then go to View/5 Menu Bar

if theres nothing in there type "Commands" and click OK.

If the Commands menu suddenly appears you might want to get a new mIRC, or copy paste these default lines into where you just were(the popups editor)

Code:
Commands
Join channel:/join #$$?="Enter channel name:"
Part channel:/part #$$?="Enter channel name:"
Query user:/query $$?="Enter nickname and message:"
Send notice:/notice $$?="Enter nickname and message:"
Whois user:/whois $$?="Enter nickname:"
Send CTCP
.Ping:/ctcp $$?="Enter nickname:" ping
.Time:/ctcp $$?="Enter nickname:" time
.Version:/ctcp $$?="Enter nickname:" version
Set Away
.On:/away $$?="Enter away message:"
.Off:/away
Invite user:/invite $$?="Enter nickname and channel:"
Ban user:/ban $$?="Enter channel and nickname:"
Kick user:/kick $$?="Enter channel and nickname:" 
Ignore user:/ignore $$?="Enter nickname:"
Unignore user:/ignore -r $$?="Enter nickname:"
Change nick:/nick $$?="Enter new nickname:"
Quit IRC:/quit

billythekid