You could Burn a copy of Taldren Software Inc folder with all contense inside it, a copy of the v2552 patch.. then if you need to reinstall OP, you can patch with v2552 patch, then just copy the Taldren Software Inc over the rop of the ony you just reinstalled.. it will fill in the missing files that way.. then you can run all the EXE files located in the Taldren Software Inc folder (except v2552 since you already installed it)
just don't forget the 2 shortcuts for the single player campaigns on your desktop and the Shipedit OP shortcut...
hope that this helps.. although to save room on a CD, i would be much easier to DL the package again or do a search on your entire system for the OP Enhancement in the event that you may still have it...
since the big package is 181 MB, it is much less space than copying almost 900 MB to disk...
if you decide to Dl it again.. just choose Save instead of Open.. then point it to where you can easily find it.. that way you can burn it to disk and no longer need anything except OP Install CD and OP Enhancement and the OP CD Key.
hope this helps.