You need money fast? Well, all - Transport Tycoon
You need money fast? Well, all you have to do is wait for a company to ask you if you want to buy their company.
Say 'NO' and go to their company information screen and buy 75% of their company and move the window to the side of the screen and keep it there for three months game time.
Save whenever you stop doing something!
After 3 months if the company goes bankrupt the company value should be in the bazillions.
Sell whats left of of the company and BIG BUCKS in no time at all!
NOTE: This only has a slim chance of working and the computer may crash.