Ok, now that I have spent way too many hours researching this I believe I understand what is occurring. This is an issue between the way Google Ads and Microsoft IE behave, it appears the specific reason that this happens is Google has circumvented IE 9's P3P Policy regarding third party tracking cookies. There is an explanation from Microsoft:
http://www.iegallery.com/en-US/tpl/FAQ
I found a fix that worked for another forum that was having this issue and I would like you to try and see if this works for you only if you are having this exact issue. It is listed for IE9 but doesn't look like it works for older browsers. (really update your browser if you are not using at least IE9)
How to stop the problem:
1. Click "tools" in your IE 9 browser
a. If you do not see “Tools” in your file menu:
i. Right click your browser header and select/check “Menu Bar”
2. Click "tracking protection" from the menu
3. Half way down the page click on "Get a tracking protection list online" link
4. Scroll down the screen that pops up and Click the "Add" button for "Stop Google Tracking" from the list
5. Click the “Add List” Button on the screen that pops up
6. Close the browser Window that popped up
7. Close the manage Add-ons window
8. Click "tools" then "delete browsing history"
a. Select 1. "Temporary Internet files and website files", 2. "Cookies and website data" and 3. "History".
(Doing this will most likely make you have to enter passwords again on websites) You can try 1 and 3 first to preserve website information to see if that works and click the "Delete" Button.
9. Close IE 9 browser and then reopen
The above fix has been reported to work for many IE9 users, since I cannot replicate the issue on my computer I cannot verify that this does work. From what I have read this issue has not been reported for users of IE10 that I can find, so another option you have is to upgrade your IE version to 10 as well.
Good luck and let me know if this helps with the issue.
Courtland