Incomplete display of web pages

Hello,

Some of the machines I have to look after must work with a low resolution display ( 800 x 600 ) for a variety of purposes.
On these machines, some web pages are not completely displayed, and no scrolling bar is accessible, so some links are out of the screen and out of reach.
Is there a workaround for this ? It happens with Firefox 2 and IE6 and 7, under Win98SE, XP Home and XP Pro.

Thanks for your help !