I've read over the other threads asking which graphics card and such is better, and I have some ideas as to which ones would suit my needs.  My question though is how do I know if the graphics card I buy at the store will fit into the slot I already have?  I'm not a computer guru, but I am in need of an upgrade. 

So basically what I want to know is how do I know what will fit into my computer?

Ah yes, the old, "What slop is that?". OK, let get started.

Right now there are 2 type of slot that take GPU Card, PCI-Express and the old AGP. If you have somewhat of a new PC then it PCI-E. If it older then you have AGP. The real way to know what you have is by checking your PC or motherboard manual.

But you need to also check your power supply, see if it is enough. Also, this is somewhat obvious, but SLI requires special motherboards.

Yeah, after some research I found out I have a PCI Bus (I'm talking way over my head here so sorry if I sound a bit stupid on the matter.)  I'm thinking that this means that I'm going to want to update my motherboard first.   I think I have my hands full.

Thanks for the help!

The normal PCI bus isnt the same as PCI-E.

Sound cards, network cards etc go in the PCI bus. PCI-E is a different slot. You need to check your manual to see what slots you have. For best performance you want a PCI-E x16

Also whats the power supply you have because I think your going to need to upgrade that depending on what card your getting

I've gotten a 400W power supply, should be here today.  I also got a 8400GS (PCI, not PCI-E -- I have no choice in this, otherwise I'd just go and buy a new pc).  And I'll be getting 2G ram next week.  It's not going to be a beast of a computer, but it will be good enough.   Everything I got should connect to my system fine.  I did quite a bit of research and so far (fingers crossed) it looks like I'm going to be alright. 

Thanks for the feedback, I'll keep this thread updated.

dude chances are it is pci express cuz you cant buy a pci graphics card lol XD they simply dont exist.

but if the card connectors for the motherboard are too small, then its a VGA card and you got a PCI-e slot on your motherboard, but if its too big, then you probably have a VGA slot on your motherboard and a PCI-e compatible graphics card.

you should probably have done more research, no offence man.

No offense, but why did you buy a 400w power supply?  On top of that, for the money you spent, why did you buy and 8400?  Next time ask people who know before you spend your hard earned money.  You've completely screwed the pooch on this one.

lol, more research?  It's working fine, i did what I could afford to do.  Thanks for the criticism, I'll make sure you guys are the first to know about my future projects.

if it works then why worry - everywhere has people that make stupid comments