talkmagic.co.uk

http://www.videolan.org/vlc/ check out this free open source video player.

I sorted it out now.... I had a blonde moment as due to years of excessive use of intoxicants my memory actually forgot that the bundled CyberLink PowerDVD software was actually included software so that DVDs would run on Vista without having to purchase a decoder or upgrade to Vista Premium... hence why my computer worked fine when initially bought and all software was installed, whereas on reformatting (and hence not bothering to install said software) it apparently stopped playing DVDs erratically. Absolute silliness. Still might give Linux another go tho.