Just upgraded to Windows 10 on my (~5 year old) laptop, and overall I like it; however, I've got one little quibble with it that I haven't yet found a solution too... When attempting to use the scroll wheel (either through the touchpad or with and attached wireless mouse) I can't scroll within certain windows. Specifically, the Start Menu, Settings Screens, the Windows App store, etc. Other windows work fine (i.e. Chrome, Minecraft, Windows Explorer) but not these ones.
I thought it might be the Synaptics driver, so I reinstalled it, but that didn't have any effect.
What's doubly weird about it is, it'll actually work for a couple seconds after I login, but then inexplicably stop working. I'm guessing there's some software loading up not long after I login that's causing the issue.
I haven't yet tried booting into safe mode, or disabling start up software with msconfig. I'll try those and update the post with the results.