I'm not much of a techie folk but...
If you use Firefox you can click on Tools > Clear recent history> and from the list check the box marked "clear cache"... I'd unclick everything else if it has a box checked.
I think newer versions of IE have a "delete browsing history" that will clear it's cache.
There are also free software progs that will clear the cache and do several other useful tricks. JetClean is good and safe for a beginner.
Do you have a slow connection or do you have images from PC blocked?
I have 3GB connection and sometimes this site is still slow.