photoshop issue

Hi guys,

First I thought I'd introduce myself to forum after joining today. My names Mitin and am a freelance multimedia designer, whos been freelancing for over two years now.

I was wondering if someone can help me with an issue I've got in photoshop which came abouts over the weekend. When typing with what ever font I use I keep getting pixelation around letters which have curves or diagnol lines eg S W R Y. straight lined letter (L I T F) are fine, dependant on the font that is being used. This problem is when viewing onscreen and has occured all of a sudden.

It may be a setting that I may have accidently changed without even being aware, and the solution may be soo simple but its one I cannot figure out. I've attached an image to give you an idea of the problem which dooming me lol, text in red are the ones that have no issue.

I have looked at the resolution and size of image etc but this hasnt helped.

Thanks guys/girls hope you can help