Taskbar window minimization and maximization not working properly

I am using 64bit Windows 7 Ultimate and lately I have had a slight problem with the taskbar.

Now If I have multiple folders open for example,when I go to the folder icon in the taskbar to see the multiple folder thumbnails pop up and pick which one to maximize,that doesn't appear.Alt+Tab doesn't work at all so I cannot maximize any of them unless there is only one folder open.

It's not like that the whole time,it occasionally triggers its self and stays like that until I reset the pc
Tried cleaning registry,cleaning disk drives,scanning pc,searching online but nothing has helped so far

Have you tried the following:

Control Panel -> System -> Advanced System Settings -> Advanced -> Performance -> Settings -> turn on "Save task-bar thumbnail previews"

It was not ticked and I thought that was it but it didn't solve the problem sadly

ThrashZone said:

Hi,
All you state is "folders" could you state what programs the previews are not working for = a browser.... ?

The problem applies for anything in the taskbar

When there are multiple windows open for a program/browser/folder or anything,apreview in the taskbar to choose which one to open does not appear and Alt+TAB does not do anything too