You can often reenter your data if you have your paperwork but suppose that is destroyed by what caused the loss of your computer. Do this if you do nothing else. If you lose your home computer your personal life will probably not be ruined but if you lose your design drawings, and your accounts receivable records, tax documents, etc. You can insure against most losses, but you may never be made fully whole. Individuals can, inexpensively, fully insure computers with a special policy or add a rider to their home owners insurance.
Businesses can find coverage through various riders, too many to list.
Business owner rents a suitable computer from a rental company. If you need six work stations those will come after an insurance check is cut, meanwhile customers can be called, email can be sent and received, orders can be taken and processed while other orders are rerouted or replaced. If you have insurance to replace the hardware, you'll probably be getting better equipment than what you had. The reimbursement will most likely buy more because you seldom can replace, exactly, what you had. Once the new hardware has been obtained, with your own software registration numbers it is perfectly acceptable to borrow, yes borrow, another user's CD to reinstall lost software on new systems.