Page Scrolls Down Automatically!

My mouse scrolls to the end of the page automatically. Even if drag the scroll bar up the computer pushes it back down. In file explorer the last file/folder gets automatically selected so I'm not able to open any other file. The problem lasts for a few minutes then it comes back again after some time.

Its not a hardware issue. It happen regardless of whether I use mouse or touch pad. I scanned with BitDefender and MalwareBytes AntiMalware. Neither of them could solve the issue. I restored to a previous point and the problem persists.

eg, when I open my facebook, it keeps scrolling down through my news feed without stopping loading new stuff and keeps going down. and If i press my windows key iam able to stop it momentarily and i can scroll upwards and when I remove my finger it starts scrolling down again.Help.

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OS Version: Microsoft Windows 8, 64 bit
Processor: Intel(R) Core(TM) i5-3210M CPU @ 2.50GHz, Intel64 Family 6 Model 58 Stepping 9
Processor Count: 4
RAM: 3943 Mb
Graphics Card: Intel(R) HD Graphics 4000, 1779 Mb
Hard Drives: C: Total - 428470 MB, Free - 106281 MB; D: Total - 25599 MB, Free - 8081 MB;
Motherboard: LENOVO, Lenovo G580
Antivirus: Bitdefender Antivirus, Updated and Enabled