I've cracked it everyone!!
It turns out the problem was in my BIOS as the AGP aperture (where the graphics card is and uses its specified memory) was only at 50% operation - 128mb in my case, instead of the full 256mb.
Since changing that, my average fps are now 80 and thats still with all display settings maxed and VFR Scenery use with great detail!!
Thanks again to everyone for their help and advice.
I hope to build more flightsim experience now and hopefully help others like you guys helped me.
Good flying to you all.
XP Pro SP3-Intel Pentium 4-CPU 2.60 GHz 2.59 GHz-3.00 GB RAM
ATI Radeon 9600/9550/X1050 Series Graphics Card
FS2004 with VFR Photo Scenery Northen England / Airliner Pilot / Commuter Airlines Eurowings Pro