Got a few upgrades and runs very well still. We upped the RAM to 8GB and changed the HDD to SSD. This worked really well for such an old PC but this year we retired it because there were better deals to be had.
If you want to try going to the factory OS, it should run like new unless there's a hardware issue or you expect a 4GB PC to perform as well as other PCs today.
Have an HP Pavilion D7 which runs extraordinarily slow. At first I thought the HD was too full - 92%. I off loaded to usb sticks until it was 15% empty. It is faster but only by a hair. Check Disk indicates the HD is healthy. One issue maybe that it was originally a Windows 7/8 - upgraded at some point. I have visited HP website but all diagnostics as that I choose OS and 10 is not an option? Do you think reset (most likely to Windows 7/8 will help? Is there anything I can do other than off-loading that will avoid losing their files (seems to be a lot of video on the machine). Oh..it has 4 gigs of RAM.