Hi,
It would certainly help if we had the Make/Model of your Dell laptop and the Dock model and there are hundreds of variations and combinations. Of course, hoping that Neemo's suggestion will fix it for you.
If it doesn't, and you'd be willing to share your specs on the computer we can better advise you. There are many laptop and dock models that have known problems, and I've seen quite a few over the years. We can suggest some things.
The symptoms you suggest point to a system failure in the laptop however. Do any of these problems you listed occur when the laptop is NOT plugged into the Dock, or do they only occur when the Dock is plugged into the laptop? It would be helpful to know that.
Regardless of the answers, have you tested your Hardware yet? Specifically
Hard Drive and RAM memory sticks? If you are the original owner of this laptop and you've never replaced the hard drive on it, chances are very high that your hard drive is failing or has failed entirely. You should know that modern era laptops (ones made in 2009 or later) have Hard Drives that are only designed to last 2 years;
your laptop is 7-8 years old and the older your laptop and it's original Hard Drive are the more likely you have a failing/failed Hard Drive which needs replacing.
Replacement Hard Drives are available online for under $100 for most laptops these days.
Should you wish to test your Hardware yourself, take a look at my free
TROUBLESHOOTING GUIDE here:
Windows 10 - Unclickable Task Bar
Thanks and Good Luck to you,
<<<<BIGBEARJEDI>>>>