hi andyp85, this is probably caused by microsoft update kb3013455 which can cause font rendering issues on vista:

After you install security update 3013455, you may notice some text quality degradation in certain scenarios. The problem only occurs on systems that are running Windows Vista SP2 or Windows Server 2003 SP2. Microsoft is researching this problem and will post more information in this article when the information becomes available.

^{https://support.microsoft.com/kb/3013455}

Thank you very much for your speedy reply.. and yes this only happened since the last update. Damn MS! Thanks again. :)

you could try if an update of your graphics driver can improve things: https://downloadcenter.intel.com/Detail_Desc.aspx?DwnldID=17407

Sorry for the late reply on this...

Thanks for the suggestion but the graphics driver is the latest one...

Thanks again AP

http://answers.microsoft.com/en-us/windows/forum/windows_vista-windows_update/kb3013455-ms15-010-causes-font-corruption/8640d38d-19bd-46b6-9af0-6213c05107d3

More info on this...