Touchpad and mouse not working (well): vostro 1015

I have Dell Vostro 1015, the touchpad stopped functioning well. when I try to move the cursor it starts moving randomly. tried reinstalling the driver, tried new operating system (tried windows 8.1 64 bits, and tried windows 7 32 bits), nothing worked. 

so I thought the problem is the touchpad and it's affecting the USB mouse, so I opened the laptop and removed the touchpad part (unplugged its cable to the motherboard), the USB mouse worked fine for a short time then it stopped working, it works for a while then it stops, then works then stops. tried more than one USB mouse, and they work fine on other computers.

When I restart the computer and enter to the bios, same  problems.

I'm planning on flash the bios, but I don't have a battery and that processes requires the battery on.

I might find one later, but not now, so what are my chances to fix this ?

a friend of mine told me it might be because of the chipset on the motherboard, could it be ? if so, is there a specific circuit that causes the problem ? which one ? and if I took it off, would the USB mouse start functioning well ?