IE7 Browser Page Mysteriously Vanishes After Loading

I'm trying to help a neighbor with his PC. Last night he started having a problem (just all of a sudden out-of-the-blue) with no apparent reason or self-inflicted cause. He said he had not done anything unusual on his PC, and had only replied to a few emails over the last couple of days from family members (which did not have any attachments). He is using IE7. Here is what happens: When he opens a browser page (his home page is the Charter Communication News home page for customers), as soon as it finishes downloading (within 2 seconds) the browser page just disappears...as if it was exited. All other aspects of his PC works fine.

Here is what I did: I ran his three virus protections (AVG, McAfee & Nortons) as well as Ad-Adware, which only found low risk items that were deleted. I cleaned up his files, cookies, etc. and defragmented his hard drive. After re-starting the PC the browser page stayed up a little longer (maybe 4-5 seconds)...probably because I had deleted the cookies and it just took longer to fully download......