My laptop suffered from multiple problems. Since bios didn't keep the time Windows was unable (who knows why) to update itself. After setting the time there were 104 updates, starting since 2010. At first Windows needed to update the update system itself and then it took a couple of attempts and errors to update everything. Some updates failed, but I think they were covered by newer ones. SP1 failed too, but manual update was a success.
The reason why Windows had not been updated was no internet connection. Fixed it by loading manufacturer's drivers (.exe with manual update overriding the idea of Windows already having up to date drivers). Then WPA2 and internet started to work again.
Still need to change the bios battery. You can't buy one I guess (for Amilo Pi3560 model), but it's some kind of small battery covered by plastic "sock" (I don't know how it's called in english).