The laptop started as Windows 8 and the upgrade is the free 8.1 upgrade?
If so I'd talk to Lenovo as they tend to do their own thing and have a better idea about if your system... whatever that turns out to be, can handle 8.1.
1. the upgrade comes from the Microsoft store and you have to tell the store not to keep downloading it if you don't want/ can't use it.
2. the Microsoft upgrade is for 8.1 which is unstable and needs (at least) the 8.1.1 patch to be worth a spit.
p.s. a factory reset is the normal & best option to remove a failed Windows 8.1 upgrade and return to Windows 8 but again... talk to Lenovo first.