Hi Jacob Martin.
Thank you for reaching out here in the Microsoft Community.
In your description, your computer is experiencing lagging and abnormal input when using the mouse and keyboard.
I note that you have tried to open the Task Manager using “Ctrl + Alt + Shift”, and at the same time, tried updating Windows and virus scanning. Thank you for your efforts and attempts to resolve this issue, and I understand the frustration and inconvenience of having a computer that is experiencing typing problems at the moment.
We are also a bit puzzled about the problem you mentioned.
The problem could be from your external device itself, or it could be the effect of some management software, or drivers.
Therefore, below we will provide some steps to test the problem, and based on the results of the test, we will determine what the problem is.
Are you using the same external devices (mouse and keyboard) on the old computer and the new one?
If so, please try using other external devices such as the most common USB keyboard and mouse. You can also try using a mouse and keyboard with a different connection, such as via Bluetooth, to see if the same problem exists with devices with other connections.
Also, is there some management software for these peripherals? If so, please disable or uninstall them temporarily.
First determine if the problem is related to software interference. To determine this possibility, I recommend trying a clean boot which starts Windows with a minimal set of drivers and startup programs. It can be used to determine whether a background service or program is interfering or causing a problem.
These steps of "clean boot" might look complicated at first glance. However, to avoid any trouble for you, please follow them in order and step-by-step.
In a clean boot, test with only the least amount of software open to see if the same problem exists.
To troubleshoot the account profile error, please create a new local administrator account by referring to the following link
Manage user accounts in Windows - Microsoft Support
In the new local account, open as little third-party software as possible and test to see if the same issue exists.
This issue could also be driver related, to determine this possibility, please refer to the link below and enter Safe Mode with Networking.
Windows startup settings - Microsoft Support
Check if the same issue exists in Safe Mode with Networking.
The above steps are not the final solution, they are more like checks, please try we will determine the problem for you based on the results after these checks and will continue to help you after confirming the problem.
Thank you for your understanding and support.
Best regards,
Zev - MSFT | Microsoft Community Support Specialist