ie8 not working right

for about 2+ weeks, browsing the net has been horrible.. ie8 is not working correctly. pages don't want to load. some load partially, some times just the header of the page loads only. some times refreshing will load the page, then refreshing won't load(the spinning animation on tab will keep spinning). most of the times i have to open in new tab to get pages to load. even getting to this forum i had to play games to get it to load fully... it's any site... just for the fun of it i went to google and just started clicking random links as fast as i can and after about 10 clicks the problem started

ie8 doesn't give option to repair, reinstall or even remove.

dell 2400

winXp

i'm running zonealarm(free) avg(free)

i defragged with;

Fragments       File Size       Files that cannot be defragmented
1,320           328 MB          \Documents and Settings\All Users\Application Data\avg9\Dumps\IEToolbar.dll_129100674975625000_f.dmp
5,420           1.14 GB         \Documents and Settings\Owner\Local Settings\Application Data\Google\GoogleEarth\dbCache.dat

i deleted these 2 files in the hope it had something to do with the problem...

how do i find the cause to repair this problem???