You need to open a business account first, and it is dependant on what kind of credit problems you have had.
A business manager will want to see a business plan with projected sales/overheads etc before they will look at a loan. The best bank to approach is the one where you have your personal account, as they know your history, and loyalty goes a long way. If you need a loan to start your business up, you may be better of with a personal loan in your own name - check out the best deals on line.