Switch off. Switch back on but keep repeatedly pressing the F8 key . The screen should give you a safe boot option. Again, if the options give you a time window to pick a safe boot from, pick a date prior to the one when your keyboard became inoperable.
"Safe Mode is a special startup option, available in every modern version of the Windows OS. When engaged, Safe Mode starts the operating system with only the essential functions, drivers and services required for Windows to work properly: installed programs that run on startup will not open, and non-essential drivers will have to be manually enabled. Internet connectivity options will also be disabled unless a user specifically requests them (by using the "Safe Mode with Networking" option)."