IS non-compete enforcable?

Yes, non-competes are enforceable, and there is no need for the company to sign it: when person (or company) A gives an agreement to someone else to sign, the fact that person/company A provided the agreement shows that they agreed to it (they would not have provided it otherwise), meaning that no signature is necessary.
However, North Carolina and other states will only enforce non-cometition agreeents to the extent they are necessary to protect the employer's legitimate interests and are reasonable; courts will not enforce excessive terms (in regards to either length or geographic scope) and will "blue pencil" an agreement to reduce it to a reaonable level. A two year agreement is almost certainly excessive and unreasonable, unless you had been an owner of the company and signed the agreement as part of a sale to a buyer who then become your employer (when you are paid for your share or interest in a company, the courts regard a longer agreement as reasonable, in light of the money you received; and also regard the buyer as needing more and longer protection from someone who has shown they can create and run a competing company). Generally, non-owners may be tied up by noncompetes for 6 months to a year. It is also possible that North America will be viewed as too large a territory or geographic scope to be protected, though this depends on the industry and your job--i.e. did the employer compete continentally? Was your job so senior that you had contintent wide scope or authority? Etc. Generally, the protected area must relate to how much protection *this* company reasonably needs from *you*. So if you were to challenge this agreement, it may well be reduced in length and area. A good idea would be to bring the agreement to an employment law attorney to review with you (and review the facts of your job, your employer, its market, etc.) in detail, to get a better sense of the degree to which it may be enforced against you.