Big problems with the file explorer, mouse and keyboard

I purchased HP ENVY h8-1440eo Core i7-3770/8 GB/1 TB + 16 GB SSD/GeForce GT 640 3 GB/Windows 8 64-bit while ago. I've been using it for about month now. First everything was working fine, but now some weird problems have appeared.

First of all the wireless mouse and keyboard keeps laggin and cutting the connection quite regularly. It feels like the wireless connection cuts at a very fast pace but I'm almost certain that the problem isn't in the wireless conection. For example when you move the mouse from left to right the movement stops couple of times during the movement for a very short time. This problem appears regularly but not all the time. I have opened task manager when this happens to see if this is memory or CPU related, but it isn't. Memory usage has never been over 40% and CPU usage has never been over 10% when this happens.

Other even weirder problem is that the programs can't access file explorer. For example when I try to use Save file as.. or Save image as.. function via Firefox or Chrome browsers file explorer doesn't open at all. Nothing happens. If I try to load a file attachment from webmail via those browsers it asks do I want save the file or open it. When I choose save nothing happens. If I use IE10 everything works fine. Today I noticed that the file explorer doesn't work right anymore even when I use Notepad++ as seen in the Image below (I can't navigate backwards since it doesn't show anything in the left side of the explorer).

I have never had problems like these in the previous versions of Windows. Is this OS related or is there something wrong in the hardware (for example 16 GB SSD cache)?

Thanks for your help.