Not sure how to get it back into computer manager, but you can build another
management console:
Start, run, type mmc, click OK. A window will open called console1.
File menu, add/remove snap in, which opens a window, in there click add,
which opens a list of snapins: select diskmanagement, click add, window opens
to select computer, select 'this computer', click finish; that window closes,
showing the list again; select defrag, click add (it won't ask which computer
this time).
select any others you want, or click close, then click OK. It returns you to
the console with the snapins you added. File menu, save as, give the console
any name you like, with .msc extension, I suggest you save it in admin tools
folder for easy access.
Note that the computer management console does not (at least in XP home)
have the option to add snap ins.
