CRM has some built in rules that stop you from deleting Companies that have outstanding actions against them.
Below is a complete summary of those rules.
You can delete a company if it has:
No Communications with status = 'Pending'
No Oppos with status 'In Progress' or 'Won'
No Quotes with status 'Active'
No Orders with status 'Active'
No Cases with status 'In Progress'
Here is the SQL used to check this by CRM (for Company ID 1227):
SELECT * FROM vListCommunication WITH (NOLOCK) WHERE Comp_CompanyId=1227 AND Comm_Status = N'Pending' AND Comm_Type <> N'RecuMaster'
SELECT * FROM vListOpportunity WITH (NOLOCK) WHERE Oppo_PrimaryCompanyId=1227 AND ( Oppo_Status = N'In Progress' OR Oppo_Status = N'Won')
SELECT * FROM vListQuotes WITH (NOLOCK) WHERE QUOT_DELETED IS NULL AND Oppo_PrimaryCompanyId=1227 AND Quot_Status = N'Active'
SELECT * FROM vListOrders WITH (NOLOCK) WHERE ORDE_DELETED IS NULL AND Oppo_PrimaryCompanyId =1227 AND orde_Status = N'Active'
SELECT * FROM vListCases WITH (NOLOCK) WHERE Case_PrimaryCompanyId=1227 AND Case_Status = N'In Progress'