Internet Explorer - web addresses history

[#1]

In this, the latest of several problems I have asked for help with, I am having problems with Internet Explorer.
On the Internet Explorer page, at the top where the web address is typed, there is (or used to be) a dropdown list of the web addresses I have accessed recently. For some unknown reason, it has been cleared of these addresses, and doesn't seem to want to remember anything before today.
Could I have wiped this memory accidently, such as using delete commands on the wrong directories/files? Is there some setup that affects whether previous addresses are remembered or not?
In Control Panel, there is under Internet Options, a thing about how long the history of your web usage is remembered. I have got that set to 20 days.
Thanks for any help offered.

[#2]

Use Firefox 
However using IE7 this is how to check your settings

[#3]

Thankyou, OldJim

[#4]

Spybot and some adaware type prog delete the history as it could be a security risk(very small but you dont want the wife knowing what you have been looking at). If you have used one of these it may have cleared it

[#5]

Thanks OldJim and Samuria