I have encountered the same problem today after doing some boot speed-up optimizations, and I found the following solution:

- Run regedit.exe
- Navigate to HKLM\System\CurrentControlSet\services\usbhub
- Change the Start mode from 3 (manual) to 2 (automatic).

This makes the USB drivers load earlier - early enough to have my USB mouse up and ready when the desktop appears. (I use Auto-Logon. Did not test if the mouse will already be available on the login screen, but I guess so.

By the way, for me this also solved another (common) problem: Printer spooler error messages regarding event ID 315 - something like "the printer XXX cannot be shared" - no longer appears in the event log for USB printers.