Keep getting large blank Microsoft IE boxes

They cover 70% of the screen and have to be minimized in order to continue web activity (typing, going to other pages etc). They are empty and have "about blank" beneath the main title listed. They don't show up all of the time either. I thought it might have something to do with my popup blocker and disabled it to no avail. I did a hijackthis and presented it on another computer sight (I was having to do an email change that kept me from posting) and they said it was clean. I run XP and IE7 but it was doing the same with IE6. I upgraded to IE7 in hopes of ridding the problem. I don't like IE7 as much as 6 but was told by our Information Specialist at work that IE7 was almost a must requirement in a lot of cases in order to run things properly. I thought that statement by him was a bit of a crock but what the hey. I know some things require at least IE6 but hadn't ran accross anything yet requiring IE7.

 

It doesn't happen here and I will make a note of the sites it does happen at. I should have noted it before but didn't think it was important because of it happening so often. It has lessened lately but will make note when it does occur.

 

I turned my popup blocker on and it may have helped my problem a bit. It was on ealier when I started having these problems so I don't know why it's helping now.