Help... Shift Key is virtually stuck...

hi .. I have a HP envy 4 , and just recently, the most annoying thing happened to it.
The shift keys are virtually stucked.. i could not type decently and enter passwords correctly. It seems like they behave like they are depressed.. sometimes they go back to normal, sometimes they trigger again.

i've gone to other forums and tried the solutions they suggest:

upgrade bios
uninstall synaptics touch driver
press shift key twice while the virtual keyboard is on display
press shift key when wifi is off
i even tried using with other HDD with win 7 , and then the same thing happens

i dont think its a hardware issue.. its working fine... i dont know what triggers it.. i started to notice this when i installed ofice 2013 plus.. i even uninstalled it.. but the issue is still there... this is driving me nuts...

can anyone help me please....?????? to HP , i've seen this a lot on this forum... dont you have a fix and rootcause??