If you just need an analogue simulator, try Analog Devices LTSpice XVII.If it's PCB design, are you doing a single layer with a few components and DIL devices, or eight layer boards with ball grid array chips at the other extreme. Do you have a budget, or want something free. What operating system are you using.Look at this link EDA packages for a start. Look for the features you think you need, keeping in mind that you may need more as times goes on. For each of your choices you should be able to find reviews on the web, and come back to the forum as well,cheers,Richard