My Computer is :-

Intel Pentium III 1.2 GHz
Intel 810E Chipset
Avance AC'97 Audio
80 GB Harddisk
128 MB RAM
No AGP Slot In Motherboard

Now What are minimum requirements for Vista?

I want to know if it is useful to upgrade my present system or it will be totally useless and I will need to buy a new computer in any case?

Let's say, suppose I upgrade my RAM to 512 MB, get a Graphics Card (that can be put on PCI Slots) will that do the job for just running Vista?

Also , pls tell me does Graphics card come for PCI slots or not? I am not sure abt this thing. One of my frnd claims that 128 MB Graphics Card does come for PCI Slots and they are called VGA Cards, but I am not sure. But say, if cards like that come, will that be useful if I buy it and later upgrade to Pentium 4 or Dual core? Will that Graphics card work in Pentium 4 or Dual Core motherboard?

Actually I am quite confused whether to upgrade my present system or get a new one. I really dont know if it is really a good option to get a PCI SLot Graphics Card because I have always heard of AGP Cards.

But most importantly, pls tell me every single minimum requirement for Windows Vista.

thanx in advance!

Let Microsoft itself tell you:

http://www.microsoft.com/windowsvist...y/capable.mspx

I'm no expert but here you go my two cents. You're especially low on RAM and believe me, you don't want to be. Windows in general is a natural RAM eater --more so Windows Vista-- and take into account that you'll need more to run other programs, nowadays all waste loads of RAM --this is tenfold true for open source programs. As for myself I'm fine with my XP even though my computer is new and "Premium Ready PC" and I'm not going to change my OS, but even if you want so badly to run Vista for some reason, I wouldn't recommed doing so with less than 1 Gb of RAM; I woun't recommend anyone using Vista if his machine isn't "Premium Ready", even if it's "Vista Capable", he would only get a slow and cloggy machine. Anyway the RAM is most easily expanded compared to other features. Also I heard Vista has 3D features so the graphic card does matter.

I wouldn't run Vista on that machine! Stick with XP. The specs are simply not good enough to get any performance from Vista. Buying a DirectX 9 capable PCI videocard would strictly make your machine capable of running Vista, but it would be sloooooow. Does Vista offer you anything you absolutely need? If so, buy a better PC, if not, stick with XP!
Oh wait, your RAM needs to be at 512 at the very least.

As for your other questions: buying a PCI video card in order to use it in your next PC would be a mistake if you ask me. Modern motherboards all have PCI-express slots (even AGP will dissappear in a year or two). So plain PCI is obsolete! And VGA-card is just a name for graphics card (there used to be a real difference when there were CGA and EGA-cards around as well, but all cards support (S)VGA nowadays).

The largest memory video cards for plain PCI slot I heard of have 64 MB.
Anything above that is either for AGP or PCI-Express (which is a completely different thing from normal PCI slot, don't let the name confuse you).

Stick with whatever Windows you ahve on your current machine, 128 MB is barely enough to run XP.
There is something like standarization and modular construction, you know... the bottom line: as long as the motherboard has a compatibile slot, the graphics card will work (unless you screw up with the drivers).
Compare yourself: PCI AGP PCI-Express
New video cards will come for PCI-Express only. I sincerely doubt that after GeForce 7800 GS AGP any new AGP cards will be made.

I wouldn't recommend you to upgrade that PC, it's a waste of money, rather buy a completely new configuration if there's any need for it.

Plus I wouldn't install Vista cause it's too new. Let them close there security gaps and fix their flaws and errors. I'd use Vista not before April '07.