computer question

help….please.
I recently upgraded, okay changed completely, my home pc. As an operating system I have moved from win 98 to XP. Problem is that now when surfing the web, I am not able to see all the pictures I used to to be able to view. Earlier today I was on a flight sim site and was unable to view the downloads page…getting little boxes with red cross in them…..even though I was able to see all the piccies with my old setup.

Is there a setting that I have to alter in XP ?

I know nothing about XP so an idiots guide would be very much order of the day and appreciated.