Using Youtube on Older Machines

[raysr11]

I installed Linux Lite 1.0.8 on a Emachines T2341.  I can't get any videos to work.  No YouTube or embedded videos.  I'm thinking that maybe the computer itself.  The video will start to work, a black screen, then will quickly disappear.  The old computer is very hard to find a video card that will work, ddr.  I installed Lite on a brand new 160 G HHD.  It was very speedy at first then I let Lite upgrade and it became very slow and sticky after that.

I have Lite installed on and older Acer small laptop and it works great on it.  Does anyone have any ideas how I can get Lite to work better?