I saw this before, this has nothing to do with the OS.
The only thing that CAN involve something like this is your browser and how it renders the page.
I had this bug on FF before, It can't display a .php file right because something has been modified.
PS: Guys, he's on windows XP (Look at the icons in the tray, then tell me if they make Intel Graphics Media Accelerator for Ubuntu/Linux or make the same wireless networking icons)
Also: I've looked this up, all the cases I've seen are due to infected files and that would require a re-installation (ffs)
I doubt it's a big issue.