Quicken 4, like from 1994? See http://quicken.intuit.com/support/help/install--register--and-convert/how-and-when-to-use-an-intermediate-version-to-convert-older-versions-of-quicken/GEN82211.html, which includes:
Here's how you'll decide which intermediate product (or products) to use for safe conversions. Do not install your new version until completely the first step(s).
If you are using Quicken 1 - Quicken 5, it's a three-step process. First, convert to Quicken 6. Next, you'll need to convert to Quicken 2004. Then you'll be safe to convert your file to whichever Quicken product your going to use (such as Quicken 2013).
If you're using Quicken 97 - 2003, you'll only need to convert it once -- use Quicken 2004 for Windows as an intermediate -- before converting to the version of Quicken you'll end up using.
Quicken 6 and Quicken 2004 has been tested and will install and run on the latest Windows operating system through the conversion process.
Theoretically, 1; I have not tried it, but you could probably install it on another computer or 2 without an issue if it's for you own personal use. Intuit would probably get upset if it saw the same registration key pop up a few hundred times, indicating it's probably being sold illegally.
I cannot answer if they fixed all the numerous problems. I did find out that my credit union web site is so out of date that it's causing some of my problems. Quicken is on Facebook, and after constantly writing about their product, I finally got a response from someone that cared and contacted my credit union web designer. I have added different accounts from other banks into my Quicken, and they are working correctly.