I never have problem with IE8.No slowdown here and running well in my XP Pro SP3.
anyway,glad to know your fixed the problem,Ice.One thing I don't like IE8 is old fashion User Interface
You can simply try this steps :
1.Uninstall JRE 6.15 via Add /Remove Program
2.Go to C:\Program Files. Delete all Java folder traces left .
3.Install latest version Java as Andavari gave or this LINK
hope this helps
why wasting time to install Adobe Reader ? its bloated
There is another good readers like FOXIT or PDF-Xchange Viewer to try.
Foxit is light and I used it.PDF XChange Viewer has more features.
BTW, HERE to fix your problem.