I finally managed to get the dvd drive to recognise the installation disc but couldn't repair so decided to bite the bullet and format.
Encountered nothing but problems with the screen keep turning itself off. This happened all throughout yesterday. Wondered if it was anything to do with my new monitor (bought a couple of weeks ago) so re-connected old monitor.
It still kept turning itself off so decided it might be the Video Card drivers. I could not get them to update so took it back via System Restore to SP2, but the monitor still kept turning off. I reckoned I needed a new video card so opened up the tower and it seems to be built in to the motherboard. So I decided a trip to Maplins was in order for tomorrow..
But then I decided to format again, once last time, and put everything on in the usual order. I went to turn the monitor on and it's now stuck on the motherboard splash screen.
So I have made the executive decision to invest in a whole new base unit. My current one is 6 years old and I am running XP on it. I guess a new video card would be around £80 and there is no guarantee that nothing else will go kaput in the near future.
I have been debating about buying Windows 7 for a while (I have two laptops running on it) and it's included in the price of a new base unit. £249 for the most basic Dell Inspiron 570 but I am hoping I can upgrade it (especially HDD's) as and when necessary