hi ricky
your current graphics solution is a intergrated graphics processor more commonly known as a i.g.p and is part of your motherboard,this saves money when manufactuers build systems as todays i.g.p.s are far superior to the first generation of igp,s such as "sis" and "s3" adapters
however to upgrade your current graphics configuration you first need to discover what graphics bus(slot) your motherboard supports,for example pci-express or agp,or in some cases the standard pci bus
there are a few methods of finding what type of graphics bus your motherboard uses,the first is the easiest and involves removing the side panel on your pc case and physically inspecting the motherboard,then compare what you see with these images(jpeg) of the most commonly used graphic buses :
pci-express x16 :image:( http://www.karbosguide.com/books/pcarchitecture/images/828.jpg)
agp x8 : image: ( http://www.criticalcables.com/Images/help/PICTURES/agp_slot.jpg)
standard pci bus(found on all motherboards(up to 5)) : image : ( http://www.hothardware.com/reviews/images/tualatin/pci_slot.jpg : the white slots)
compare these images with your motherboard and this should allow you to discover which graphics bus you have
upgrades : well theres not much use recommending too many compatible graphic cards however i shall recommend one agp card and one pci-express with both costing less than £100 and both capable of running all of todays games including crysis,world of warcraft,bioshock and call of duty 4 !
1) agp x 8 : for the agp bus i have to recommend the fastest agp card you can currently buy,the Sapphire Radeon HD3850 512MB GDDR3 TV-Out/Dual DVI 8xAGP( http://www.novatech.co.uk/novatech/prods/Components/Graphics-ATI/ATIAGPSeries/Sapphire/11124-00-20R.html) is a mammoth of a agp card and has some excellent specifications which include a 668mhz core clock and 512mb of gddr3 memory running at 1656mhz,combined with the healthy 256bit memory interface and you have a memory bandwidth of 52gb/sec,this is a extremely fast agp card and as allready mentioned you cannot get a faster agp card than this
note : the Sapphire Radeon HD3850 requires a 450watt or more power supply with at least 26A (total) on the +12v rail,you also require a 8pin pci-express power connector however sapphire do bundle a adapter(2 x 4pin molex > 8pin pci-express) with the card
2) pci-express x16 card : there are hundreds of pci-express cards to choose from however i shall recommend my own card as i can give you a honest and true opinion of the card(i have also owned the radeon HD3850(above agp card) aswell)
the BFG GeForce GTS 250 OC SLI 1024MB GDDR3 TV-Out/Dual DVI PCI-Express ( http://www.novatech.co.uk/novatech/prods/Components/Graphics-Nvidia/NvidiaGTS250Series/BFG/BFGRGTS2501024OCE.html) is a amazing card for its price and has some extremely good specifications,and these include a 750mhz core clock and a massive 1024mb(1gb) of gddr3 memory clocked at 2240mhz,however these are factory overclocked speeds and the stock speeds found in other models of the gts250 are 738mhz core clock and 1100mhz (2200mhz ddr effective) memory clock
theres a 256bit memory interface and a memory bandwidth of 71.7gb/sec(70.1 gb/sec stock bandwidth)
in regards to power reqiurements the gts250 requires a 450watt or more power supply with 24A or more on the +12v rail(s) and a 8pin pci-express power connector,however pci-express adapters are included with the cards accesories so you can use your existing molex power connectors
note : allthough 450watt is stated as the minimum power supply needed i would air by the side of caution and go with a 500watt or more,however if you have multiple hard drives and optical drives i would then recommend a 600watt as a minimum
allthough i said i was only recommending one of each i had to include this pci-express card,mainly due to its bargain price
the ASUS NVIDIA 9600GSO 512MB MAGIC PCI-E( http://www.aria.co.uk/Products/Components/Graphics+Cards/PCI-E/nVIDIA+GeForce+9+Series/ASUS+NVIDIA+9600GSO+512MB+MAGIC+PCI-E+?productId=37214) is just £37.71 inc. VAT and for this price range you would normally only receive a 64bit budget card thats only capable of office and web browsing tasks
however the ASUS NVIDIA 9600GSO is a excellent card and has some similar powerful specifications,and these include a 550mhz core clock and 512mb of gddr3 memory running at 800mhz(1600mhz ddr effective),and with a capable 192bit memory interface with a resulting bandwidth of 38gb/sec this is a ideal upgrade,especially for someone who is moving from a intergrated graphics solution
in terms of gaming performance well it should be able to run the majority of todays games on medium detail,however more demanding games like crysis may require detail to be lowered,however remember your pc,s processor plays a significant part in the games performance so if you have a intel core i7 cpu you would get better performance from the ASUS NVIDIA 9600GSO than if you were using a intel pentium 4
as with all upgrades remember to wear a anti-static wristband to avoid damage to your new hardware,however touching the side of the pc case or a radiator pipe does the same job
and for a guide to installing your new graphics card check out this website i made specificly to assist you guys with this task..you can find "installing a graphic card" at http://www.geocities.com/brianthesnail123/temporarypreviewfile.html?1251017930546
and as i allways tell other guys any problems let me know,i will be glad to help
good luck ricky !