Try deleting them and see if pages load faster.
Don't delete cookies (login info is stored there for certain sites if you need them)
I don't know what your version of IE is but this is how it's done for 9:
How To Delete Temporary Internet Files in IE9 (Clear IE9 Cache)
Here 8:
how to clean temporary internet files in ie 8
I think you're using 8 (unless you updated/upgraded?)