What invalidates an NDA agreement?

I signed an NDA agreement with a company (an on campus entity in Canada) that is very vague, contains errors and there is a multitude of issues surrounding it.
Its from legal zoom.

1: After my name (evaluator), in the 'of' field they told me to write 'programmer' and not my address.

2: There is no expiry date.

3: The individuals (inventors), and their home addresses were listed, not a company. They have a multitude of interests and endeavours I was not aware of at the time of signing. Does the agreement cover everything they do? Is this not overly broad?

4: No address was listed as the place of signing.

5: The witness and inventor signatures were put on a page which (last page) was not a page on which I signed or initialled. I did not witness this page being signed myself. (its on 8.5x11 not legal size thus the cut-off)

6: I never received a copy electronic or otherwise.

7: 5 weeks later I asked for a copy and it was refused.

8: I subsequently terminated the agreement, never having seen a copy.

9: After contact with their academic advisors they sent me a copy. I was threatened with legal action after speaking to these advisors and asking them for the document. Providing the document is apparently harmful to the company and so was asking for it.

10: Clause 16 was a termination clause, so I repeated in writing that it was terminated and claimed the possibility it was invalid.

11: The document was never notarized.

12: There is no description of the invention besides the contract boilerplate.

I've quit and I am wondering if there is a snowballs chance in hell this agreement could be considered valid by an Ontario court?

How hard is it to have the agreement invalidated?

Thanks.

You don't need to invalidate it, just don't break it. Hard to comment without knowing what you agreed to, but NDA is generally about keeping secrets until they become public domain. Just don't tell anyone what you learned (even if it was nothing). That'd be the "non-disclosure" part of the NDA, so unless there is something else you signed up to, I'd say just forget about it for now and concentrate on something positive and constructive.

As always, IANAL, YMMV, IMHO, etc.

Many of your numbered items are not relevant to enforcement of a non-disclosure agreement. It could be very hard, even impossible to invalidate your agreement. (As some of the others here point out, if there are other provisions such as a non-compete--that is a very different matter.)

Why is it so important to you to disclose something given to you in confidence? Implicit in your question is that you have already decided to disclose protected information. In your position I would have some concern about criminal aspects of taking what your were given and appropriating it elsewhere.

If you have disclosed protected information and are being challenged, this is a serious matter that should not be left to legal advice from an internet forum. This could have important consequences for your long-term career and you personally. As TimJ says, you should see an attorney.