Back in my previous life fixing computers & solving their problems, I found the HP laptops to be slow even on their best days. They typically come pre-loaded with so much junk. A clean Windows install will speed up the HP laptops quite a bit, but it can be a challenge finding the drivers. If you download a driver bundle from HP, that often installs a bunch of junk and immediately slows down the laptop.
As for QB 2005 not being compatible with newer Windows, that might not be the case. I still run my QB 2004 on my Win10 Pro computer and click through the dire instability warning. It has never been unstable on my Win7 or Win10 builds.
You may need to resort to keeping your Dell for legacy work and not use it for watching videos or surfing the web. Use a laptop with current software for surfing, email, videos, etc.... basically everything except what the Dell is designated to do.
I read recipes the same way I read science fiction. I get to the end and I think, "Well, that’s not going to happen."