1. Windows 8
2. Acer Aspire V3 touchpad and touchscreen
3. Touchpad and touchscreen, though I use the touchpad more
4. When this occurs, I am only able to move my Sim around. I am able to click and zoom in. When I click on my Sim or their clothing, the respective customization windows pop up, but if I try to click anything in the windows, my mouse is registered as trying to zoom or move my Sim around, as the windows are no longer clickable.
5. Windowed mode. I would play Fullscreen, but if it happens again, I would have to forcibly shut down the Sims in order to exit out, which messes up my computer screen. However, I will try.
Just in case this helps:
This tends to happen every time I play for more than four-six hours (it's hard to tell, time flies by so quickly)
The first time it happened, I panicked and started clicking around frantically everywhere on the screen. I started clicking on my Sims' portraits to see if I could switch between them and lo and behold, I could and I was able to change hairstyles, click on the basics at the top left. The issue had resolved itself.
The second time it happened, I had also been playing for around four hours. I clicked frantically on my Sims' portraits waiting for it to fix itself again, and it did. I switched to another Sim. I was able to change one thing (I think it was a bracelet) before it happened again. I clicked frantically again like an idiot, somehow managed to switch back to the original Sim I had been editing, but afterwards I couldn't do anything but move my Sim around.
Being a child of the autosave era, I don't have the kneejerk reaction to save every minute in order to not lose my data. I checked around to see if there was a hotkey for saves, with none to be had, I had to forcibly shut down Sims with taskmanager, as pressing exit only prompted a window in game that I had no way of actually clicking, and pressing enter seems to be choose 'cancel' as opposed to 'accept'.
That being mention, I should also point out that my keyboard was registered as it normally would be, so it's only the mouse. Esc, >, <, -, +, ctrl+z, and ctrl+y all worked normally.
I hope this information helps in any way.