what version of windows do you have and is this a recient problem or has it always been very slow?
are you using a dial up connection? if so and its always very slow then try installing the latest drivers for your modem.
try turning of graphics in web pages, this should speed things up but it wont look very nice and some sites may not work very well.
in internet explorer click tools/internet options/advanced and untick 'show pictures' 'play anamations in web pages' 'play videos in web pages' boxes.
run a check for spyware with adaware or spybot click here click here as this can slow things down further.
as above some more info may help a bit.