For the price of a phone call, I'll take a stab at what it will take to fix your computer. Based on your needs, I'll recommend a Linux distribution and advise you about hardware you may want to purchase. Many local shops charge for this advice. I don't have their overhead costs.
If it looks like GNU/Linux would be good for you, I'll go to your place to install it for you. I can generally do this on site, but I'll walk you through any hardware purchases you want to make. In some cases, I might recommend taking your computer back to my shop or you might not want to be bothered with the details. When I've got things working, I'll walk you a few basics and show you where to get more information. If you are not happy with what you see, I can return your system to the state I found it in and you own me nothing.
Once you are set up, I'll be happy to answer questions you have by email or phone.
For an additional fee, I can try to fix your Windows. Other people do this better than me and I prefer to avoid commercial software licensing issues. It's part of my low overhead.