Is this sentence gramatically correct-her would have been to tired two continue 2 notice anything wrong?

No, the sentence is not grammatically correct. Here's why:

* "Her" should be "she": "Her" is a possessive pronoun, but we need a subject pronoun here.

* "Two" should be "too": "Too" means "excessively" in this context.

* "2" should be "to": The word "to" is part of the infinitive verb "to continue."

Here's the corrected sentence:

She would have been too tired to continue to notice anything wrong.