Any reason why W10 would have a negative effect?
It's probably the amount of RAM. Win7 requires minimum 2GB of RAM but runs better with 4+. Win10 requires 4GB RAM but 8+ is better. It might be possible to reduce the Win10 memory footprint by turning off unused services.
I'd also recommend either going back Win7 or trying an easy to use Linux like Linux Mint. If it will run Kodi or similar software, a cheap remote would be a good way to control it for video.
Before buying the necessary VGA/HDMI converter
The video output of the Dell Latitude 2110 VGA port is analog. That means simple cable will not work. A converter with an HDMI modulator is required. The converter will also need to convert the video to a format compatible with the TV such as 1280x720p, 1920x1080i or 1920x1080p.