Welcome to the forum.
There are volunteers here willing to help you.
1st of all I will admit that I have little to no knowledge of the "inner workings" of a computer!
Here is the best advice I can give you. This is the same as I would say to my close friends. Attempting to improve or maintain an older computer with Windows 2000 is not a good use of your time. I have a Windows 2000 laptop here that works fine, but I no longer have any interest in doing any improvements on it. If it started to have problems, I would just set it aside.
You can get a good quality refurbished dell laptop for about $200 or less and it with have Windows XP. The old computer you might sell and recover part of the cost.
If you want to get a refurbished Dell laptop with Windows XP, do a Google search on:
Refurbished Dell Laptop
The best choice of wireless adapter is often a USB device. These are in high demand and work on many computers, so the cost goes down and the quality is good. But any specialized wireless devices for older models tend to be overpriced because of low turnover.
That is the best advice I can offer for anybody with limited experience. I have had better results buying a newer refurbished computer rather that doing maintenance on my older clunkers. And I have years of experience st this thing.
Otherwise, you have to remove the drivers you installed. They may not be suitable for Windows 2000. which had a major update two or three years ago. It is no longer supported.