during this episode of "disobedience" is the hard rive light flashing or on constantly .It sounds as if either some new program or utility is hogging your processor and memory during startup , or a windows update is failing to "update" correctly and trying to update continually during start up . you need to be logical ,if ctrl-alt-del wont work during tha time , wait until you can use the pc and check what has been installed or updated just about the time you started thhaving the problem ,hopefully you can remember what day it started to happen ,therefor the problem program/update would have happened the time /day before. I would check your installed programs in control panal ,to see if any program was installed at that time ,also check installed updates and see what updates match that time period . type msconfig into the seach box at the bottom of the start menu and hit enter ,check the startup tab to see what is running at start up ,you can disable suspect ones ,one at a time would be best to try and isolate the problem but be careful ,some are system and are needed . I am assuming you have already tested for spyware /malware or virus problems . there is a freeware (I think) program called "whats running" that I believe can be set to run at startup ,if it does ,it will show you all the processes running you will be able to identify the hog. good luck .
Hands-on: Samsung Galaxy S8 review