Site Favicon changed to Tesco?

Probably not a problem with this site but with my computer but the favicon for this site and for another one has changed to the Tesco favicon. How did that happen (OK I was doing a lot of browsing on the Tesco site yesterday) and how can I change it back?

Using IE7 on Windows Vista Ultimate SP1.

Update: It seems even worse. Lots of my Favicons are mixed up for lots of sites. Where do they live and how can I zap them and start from scratch?

The Favicons are stored here: (Vista)
C:\Users\User\AppData\Local\Microsoft\Windows\Temporary Internet Files
Not sure for XP

Cheers. Deleting the files in there seems to have done the trick.

How do I change permissions? Using Administrator account I'm denied access to AppData.

Even for the User Account you are logged on as?

Mmm! Mix up has returned in a different way., And I have been nowhere near the Tesco site since - although I did get a security check phone as I had used a credit card for payment which had been dormant for several months.

Time to bite the bullet and wipe the whole of my TIF folder I think.

I only have the one account Administrator. No one else uses this lappy.