The beauty of computer science is that there could be multiple, possible causes. Let's start by breaking it down into smaller, more manageable pieces. So... you just got this *new* computer or you just installed Windows 7... and you're getting this issue? Is the copy of Windows 7 genuine and is it English based? Hm... if I was in your position, I'd start by restoring the computer. Most of the time, that fixes a lot of corruption problems.
Edit: The lazy way would be to use this font: "Ebrima 12" (Attached).
It looks like this: