About 2 months ago, my son's computer got to the point it would not display a web page in IE. If he opened IE, it simply displayed a blank page. We determined the OS partition on his partitioned hard drive was getting quite full. He moved My Documents from C:\ to D:\, freeing up some space on C:\ and then his web browsing returned to normal.
How much free space (absolute and percentage-wise) on your OS drive/partition?
Also, how long since you deleted temporary internet files? Might help do do that; deleting cookies and clearing history might also help.