Just thought it would be good to refresh everyone on the particulars of "Peak Performance"...
Weapons for wargame:
"modified pulse lasers"
Status of warp drive when they board her...
RIKER: Now, what are the possibilities of warp drive?
LAFORGE: Not good. There are only a few dilithium fragments left in the holding clamps. Even if we had crystals that were intact, there's no anti-matter to fuel the drive.
RIKER: Any recommendations?
LAFORGE: No, sir.
WESLEY: We haven't got a prayer.
...
(Looking inside an empty warp core)
WESLEY: The lining's still smooth. We should to be able to do something with these dilithium fragments we scavenged.
LAFORGE: Sure, the system is functional. But without antimatter, what difference does it make?
WESLEY: Geordi, I have to return to the Enterprise.
...
Wesley has brought aboard a tiny amount of antimatter...
LAFORGE: The hard part's going to be calibrating the thermal curve necessary to start a controlled reaction.
RIKER: Assuming you can, can you regulate the reaction?
WESLEY: There's just enough crystal to do it. We plan to channel the reaction through the chips.
LAFORGE: Are we good?
RIKER: You're better than good. Great. Brilliant. It's going to be fun. Carry on.
..
And after some work...
LAFORGE: You'll have warp drive, Captain, though it may not be what you expected.
RIKER: I think that deserves some kind of explanation.
LAFORGE: We'll have warp one for about
WESLEY: Just under two seconds.
RIKER: That's not long enough for an escape, but used as a surprise it may give a strategic advantage.
...
And we do learn that the Hathaway was originally rendered "warp inactive". So the blue glow from the nacelles at the very beginning were either from the impulse systems or something that had no relationship to the status of the warp system.
RIKER: We have a limited, two-second warp capability.
KOLRAMI: Impossible! That ship was rendered warp inactive.
As to the original weapons on the Hathaway, those were stripped as well leaving just the wargame pulse lasers...
RIKER: She's really been stripped down, Captain.
KOLRAMI: The only offensive systems you'll need will be simulated by computer.
...
NAGEL: That's no ghost attacking the Enterprise. That's real!
WORF: We must assist, sir.
RIKER: With what? We have no offensive weapons.
Impulse powering or needing the warp nacelles seems to make the most sense in this case and it seems to be a TNG-specific thing, IMHO.