Since this is an old Dell laptop that puts an entirely different slant
on the whole thing. There were some replacement video cards for this
but a) they will be very hard to find now and b) reports from forums
say that anything other than the stock card was the pits to get the
laptop to recognize - and you already have the highest grade stock
card in there!!

http://www.bay-wolf.com/videoupgrade.htm for more info...

So I really think upgrading the video is a non starter :-(

However, poor performance of laptops is often the result of clogged up
cooling systems. The radiators are very narrow finned and very easy to
get blocked up with fibres and dust - seen many instances of a totally
blocked radiator with a quarter inch of felt pad !! The web site below
is about how to replace the fan but the same applies to remove it and
check the radiator for being clogged up. A small brush and blow out
will often work wonders - also brush out the fan but be careful as the
fan blades are fragile ( if you blow the dust out don't use compressed
air without preventing the fan from spinning - it will go way too fast
for the bearings and wreck it !! ).

www.ehow.com/...ange-fan-dell-inspiron-laptop.html

Step 10 - where the fan is removed - is where you look inside and
see just how much c**p these things collect And yes it really is
necessary to remove the screen - some laptops demand a total strip
down and removal of the motherboard to do this job, hang your head in
shame HP :-(

Hopefully this will restore some performance but unfortunately you are
very limited in what you can do with a laptop - nature of the beast.