You can restart a download by re-searching for the download and asking to download it again. This may restart the download from the beginning, or it may carry on from where it left off (depends on how lucky you are).

Your description sounds as if LimeWire is crashing. But presumably not 2-4 seconds after starting (you can select stuff to download) - 2-4 seconds after you start a download?

Do you know (can you find out) your operating system, version of Java, version of LimeWire?

Can you explain in more detail what it going wrong? (Give detailed details of what you see and what you do).

Mark