In the second X-Men movie, X2, Wolverine defeats Deathstrike by injecting her with liquid adamantium. Considering that Deathstrike has a healing ability similar to Wolverine's, would she come back to life if all of the [excess] adamantium was removed from her body? If yes, would there be a limited window of opportunity to perform such a procedure successfully?
This answer is purely conjecture, given the limited amount of information we know about Deathstrike from X2: X-Men United.
Due to the way that the adamantium was injected into her body, it is unlikely that Deathstrike's healing factor would've been able to save her, unless her cells found a way to regenerate a nervous system around the hardened adamantium. Wolverine's adamantium was bonded to his skeleton surgically, the liquid wasn't injected into his body haphazardly, which is how he was able to survive the process.
Additionally, when we last see Deathstrike in the film, she is both submerged and trapped in a tank of water, assuming that the injected adamantium wasn't completely surrounding her lungs, she would also have drown, in addition to any damage the adamantium caused. It is unclear how much lung damage someone with a healing factor can handle before they finally drown.
Deathstrike's best chance for survival would have been an immediate intervention from Magneto, whose power would've allowed him to return the adamantium to its liquid state and remove it from her body.
According to Wikipedia:
Kelly Hu wanted to reprise her role in X-Men: The Last Stand, indicating the she survived the fluid adamantium injection by Wolverine, but after Bryan Singer was not on the project anymore, she was not on the project anymore either. [source:wikipedia]
However no source is provided, so we can't be sure how accurate this information is. Regardless, we'll probably never know how Bryan Singer had intended for her to survive the adamantium injection.
It look like she survived, as she come back in X-Men: The Official Game, Chapter One :
In the depths of the base, Wolverine finds Hydra has a familiar agent: Lady Deathstrike, who was able to survive an apparent death in X2 after being pumped full of adamantium.
It depends totally on how graphic you want to be and how her regeneration is defined.
This version of Lady Deathstrike is not portrayed as a cyborg, but as a brainwashed mutant with regenerative abilities similar to those of Wolverine. This version of Lady Deathstrike also demonstrates superhuman strength in the film, throwing Wolverine across a room with enough force to shatter a concrete wall. The title of "Lady" was not used in her name.
If Deathstrike's regeneration abilities are reputed to be just shy of Logan's in terms of efficiency, then her resurrection could be accomplished in a number of grisly ways:
Physically removing the adamantium from her body. If her powers of regeneration are equally potent, you could simply cut the hunks of now solidified adamantium from her body and let her "return to the living state" much like Logan would.
It would be messy, ugly and unglamorous but certainly possible since such a thing would not stop Logan from regenerating once the same was done to him.
She could also opt for the cellular rejection method of superheroic regeneration. Her body could simply grow behind the now solidified chunks of adamantium until she was reformed with the adamantium outside of her body, the same way evil villains show off their power by expelling the bullets, pushing them from their bodies.
This would take a considerable amount of time, probably be VERY painful, and make for an EXTREMELY pissed off or even insane Deathstrike when she was done. She would certainly only have one thing on her mind after that. Revenge...
Actually, somehow she was able to survive the belly-full-of-dangerous-liquid event. I am unsure how, but the character is seen last not in the tube, but in the classroom with Charles in the final few minutes of the film. She was the student closest to him in the seating arrangement and there were even a few brief seconds with her face on film. I am unsure how she survived, nonetheless she did.