Why does Ctrl + Shift not let the keys I, J and U register shortly after system startup?

This issue has been happening to be for a while, and quite frankly I've been nothing but confused about it. I am on Windows 10. I've tried: Restarting my PC. Disabling Sticky keys, toggle keys and filter keys. Changed registry editor files (Start in X\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\i8042prt ) Replug in my keyboard and reinstalled drivers several times One thing of note is that, there is a small grace period when I get into my desktop, where Ctrl + Shift + I / J / U does work, but it only lasts for so long until it, once again, won't register these keys when holding Ctrl +

Question by Jericho on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.