What Internet Explorer settings could cause IE7/IE8 to not load css?

We have received isolated rep开发者_JAVA技巧orts of IE7 & IE8 not loading/parsing the css from our website built on asp.net 4 and hosted on iis 6. One user recently sent us screen shots to confirm the problem.

• They tried upgrading from IE7 to IE8 which did not fix the problem.
• Firefox installed on the same computer would load the website/css normally
• After investigating we found that resetting their Internet Explorer's settings fixed the problem (Tools -> Internet Options -> Advanced -> Reset). He is now unable to reproduce the problem

We've tried to reproduce the problem with the advanced internet explorer settings on our computers without success. Any idea what setting could have caused this problem? Any experience with similar issues? Thanks!

I have seen similar problems with various versions of IE due to malicious or poorly coded add-ons. Next time you see this you should try having them run IE without add-ons to see if the problem still exists.