For a solution to the problem, see [URL]   Kuhlewampe
Hello on Oct 14th I installed the huge Windows 8.1 update. Eversince the system works fine for about an hour after restart. Then it stalls, works again, stalls. When stalling, the application bar at the top goes "pale". I cannot enter anything during the pale periods, nor scroll the page (It took me 10 minutes to just enter this text...). However, music using the Windows Mediaplayer continues playing alright. I have an Inspiron 5521. The CPU usage remains at around 25%. The task manager list does not show anything unusual. Would appreciate any advice which will allow me to lead a normal computing life again :) Or just hear about a similar experience. Kuhlewampe
System stalling. Behavior appeared after installing the huge Windows 8.1 update 
on Oct 14th 2014