I know we cannot classify an account as a NOW account if it is owned by a corporation but is it ok that the account agreement still reserves the right to require at least seven days' written notice prior to withdrawal or transfer of any funds in the account?

No. If it is a transaction account held by a for-profit corporation and earns interest, it must be a demand deposit. A demand deposit may not include a reservation of right to require prior notice of withdrawal. See the definition of demand deposit in Regulation D, section 204.2(b)(1) at http://www.bankersonline.com/regs/204/204-2.html#demand

What about this part of the definition?

(2) The term demand deposit also means deposits or accounts on which the depository institution has reserved the right to require at least seven days' written notice prior to withdrawal or transfer of any funds in the account and from which the depositor is authorized to make withdrawals or transfers in excess of the withdrawal or transfer limitations specified in paragraph (d)(2) of this section for such an account and the account is not a NOW account, or an ATS account or other account that meets the criteria specified in either paragraph (b)(3)(ii) or (iii) of this section.

OK. I think you got me on that one. That paragraph is clearly designed to categorize as a demand deposit any account that works like a transaction account but can't be classified as a NOW or ATS. I will concede the point. It would be a demand deposit.