I really need you to answer mosre then just my last question or this could take longer than it needs to be. ya know!
so I get it you got the computer used and with the problem "starting" and its getting much worse.
Lets check first for a driver issue:
click(Start) >> control panel >> device manager
do any of the driver icons have either yellow or red symbols on them like a red "x" or a yellow triangle with an explination mark. If any icons with these or any other "tags" like these are present please tell me the name(s) of the drivers and the symbol
now in the device manager's menu, please select: View >> Show hidden devices
now preform the same "look over" and report anything marked as stated above