You may be running out disk space. To check this, open File Explorer, click on PC and you should see the hard drive and it should show amount of free space. If the indicator bar is red then it means you are running out of disk space. Windows also keeps virtual memory on the drive, it writes and reads information there to help improve the performance of your operating system. The delays you experience are consistent with virtual memory swapping on a full disk. If this is the case for you, then you can right click on the hard drive and select disk clean up.