Using the mouse only, check the motherboard settings in Control panel and make sure the keyboard layout and language are correct. Something, including an infection, could have changed it. Might not be a bad idea to reinstall the OEM drivers as well for keyboard and mouse if there are any. Often on laptops, the Synaptics touchpad drivers affect keyboard functions so you might install the latest version of that if yours uses the Synaptics drivers.
I'd also do full scans for viruses and malware. Often infections can change those settings and make doing anything impossible.