I'm getting back into some gaming and find that my computer has a "Intel 82845G 64mg Graphics Controler" I am assumming that this is the stock card that came with this computer. I'm lookinfg to buy a low end card and have found this one. GeForce 9400 1 gig card........Would this be a good starting point? It's cheap and has good reviews.........Thanx

The 9400 is OK... generally any DX10-compatible card with at least 512MB of memory is fine. But just remember that even if you had a kickass card, your other computer components has to match up to the standards, for example you can't have a GTX 280 top of the line card with say, a Pentium 4. Your system has to be well balanced, and a computer that started with a "Intel 82845G 64mg Graphics Controller" doesn't sound like a computer optimized for a GeForce 9400.

First question: what is your PSU rating?

psu rating
what kind of mobo you have
before we can even make a suggestion

Aye, PSU and mobo. As well, do you have a 32 bit or 64 bit OS?
Finally, if you're going to be doing any kind of regular gaming with more modern games, that card won't cut it.

I picked up an 8800GT for less that 70 Sterling. PCI.
Just mind that a high end 8 series will be just as good or slightly better than A low end 9 series.
Depending on your budget.

While the 88 cards are still very awesome, the problem with getting an 8800GT now is that it's EOL already. RMAing it would be a big problem, especially depending on what brand you actually get

I got XFX brand (double lifetime warranty). ;)
but yes I understand where you are coming from. I'm just hoping that this will do me so that I can skip the 9 Series and get the next gen one early next year. ( fingers crossed)

Currently you have an integrated graphics controller- pretty much as low as you can go in terms of graphics processing power. As others have already mentioned the two things you need to check are your power supply and motherboard. For the PSU you'll need to check the overall wattage (I'd recommend no less than 500 W for modern GPUs), as well as the amps on the 12 volt rail (look for at least 18 amps on any individual 12 volt rail). For the motherboard you need to check that you have a PCIe x16 2.0 slot; some older motherboards only have an AGP slot for graphics, which limits you to older cards like the nVidia 7x00 series.
As for GPUs, I wouldn't recommend the 9400; while not terrible its not optimal for gaming. With nVidia cards you want to look at x600 or x800 cards for gaming. Currently the nVidia 8800 and 9600 are excellent budget cards as well as the ATI 3850 and 3870 cards. For expensive options there's the nVidia GTX 260 and 280 (although these are a bit pricey), and the ATI 4850 and 4870, which while not quite as powerful as the GTX 280 wipe the floor with it in terms of price/performance ratio.

The most important question is do you have the slot for a video card?

I'm sure I remember seeing some benchmarks that put the 9800GTX only ever so slightly higher than the 8800GTX so the generational gap, at least between 8's and 9's isn't that significant.

Yeah that was the impression I got too, a few more features in the 9x series, DX10 compatibility and the like but not much difference in processing. When I was designing my last comptuer that I never got around to buying, I was planning to sip the 9 & go right to the GTX280s

I understand that ATI offers the best bang for your buck nowadays though. The HD4870 is quite a beast.

Beleive me I aprecieate all your help but I am allittle overwhelmed here with all the help "Cool".....I'm an old guy kinda...Don't know pSU rating, don't know how to see if my system is 32 or 64 bit....I built this system to play music "Cakewalk" and MIDI for keyboards and my guitar work and vocals blah, blah etc so my memory is maxed and will not hold anty more and a "Celeron" 2.7 gxz processor....old but functional....... Guess I wasjust look'n for a low end card to play "Descent" and other space sims...........thanx