I've had a word as you posted a log, and this section is not for logs, hence the conversion to an attachment, but from what they saw at a brief look they didn't see anything obvious, so lets try some basics, I don't have an answer to your problem, there is little to go on at this stage, so heres hoping some simple maintenance will sort it out.
Assuming your operating system is Vista as per your info under your user name, I suggest getting and running
Disk Cleaner, and
CCleaner, both are free junk file cleaners, both these WILL wipe your cookies as well, so if you use them to stay logged in at sites you will need to remember your log in details, if you want to use such cookies let me know and I will explain how to save those specific cookies, so all other cookies will get wiped.
Note:- When installing CCleaner take special notice of the check boxes, I suggest unchecking the bottom one (unless you want the Yahoo toolbar, and the 2nd one from the top I think it is, unless you want it to appear in your Start All Programs list, personally the shortcut on the desktop is enough for most.
Now with the junk gone lets check a couple of settings, launch ie and press the Alt button (if needed) to open the menu bar at the top of the browser, there are other ways but no point repeating the end result, click on Tools - Internet Options, under the general tab click on Settings under the Browser History section, highlight the number shown and type 20, next check the top option for Every time I visit… then OK to exit that window.
Next click on the Connections tab at the top, then LAN settings near the bottom, look at all the check boxes, if there are any checked , uncheck it\them, then OK that window to close it, then apply\OK to exit the main window, see how you go after doing this, for an experiment, should the same issue happen again, close the browser and run the junk file cleaners, then without rebooting see if pages load again, if they do then it suggests some space it uses is getting filled therefore blocking further content until emptied, knowing\proving this will help narrow down the best solution, hope this helps a bit though.
