okay...so i have a Dell Dimension 1100 and i was told that i cant buy another video card for it because It doesn't have another slot. So i have to buy a new motherboard with a slot but then .... when i was searching it said that i might need to upgrade my RAM when i get the new motherboard and maybe need a new power source.

so my question is how do i know what kind of motherboard to buy that will work without and probs and I also wanted to buy NVIDIA GeForce 6600 GT or any 6600 series .. will i need a new power source or RAM ? What CPU are you going to use ? ?
The one from the Dell ? ?
If so the MBoard has to SUPPORT it.Dell Dimension 1100

With that motherboard, I would keep the onboard video.The major problem that i find with replacing a motherboard in a Dell computer is that dell sometimes uses a non-standard form factor. This means that a standard ATX motherboard might not line up with the screw hole pattern in your Dell computer case. You need to find out if your motherboard is an ATX form factor and if it is not then you are limited to only BUYING another motherboard from Dell.Quote from: Computer_Commando on January 07, 2010, 01:08:21 PM

Dell Dimension 1100

With that motherboard, I would keep the onboard video.

The major problem that i find with replacing a motherboard in a Dell computer is that dell sometimes uses a non-standard form factor. This means that a standard ATX motherboard might not line up with the screw hole pattern in your Dell computer case. You need to find out if your motherboard is an ATX form factor and if it is not then you are limited to only buying another motherboard from Dell.

How would i know if its a ATX form format ??

The Dell Dimension 1100 motherboard is Micro ATX form factor 9.60" x 8.20"

Well, typing "Dell Dimension 1100 motherboard atx" into Google and reading through the results would be a start.

Firstly, you will discover its Dell part number (WF887)

Second, you will see lots of result summaries with text such as this

beware! many Dell models use nonstandard power supply connector wiring schemes so if you just replace the motherboard with a standard non-Dell board, you may have to change the PSU as well, or you'll blow both the board and the PSU together. So you are probably restricted to a Dell motherboard anyway.

You should probably get a new standard (not Dell) micro ATX motherboard and standard (not Dell) power supply at the very least. Next you may well find that your RAM is not going to be compatible, with the mother board and/or with any extra RAM you plan to fit. Pretty soon you will find that all you have left is the Dell case and the hard drive(s) and the optical (CD/DVD) drive. Cases that are better than Dell, hard drives and RAM are quite cheap these days.

I am trying to tell you (I thought I had already) that you need to consider whether the upgrade is going to be a worthwhile way of spending the money. You might be better off selling the Dell for what you can get and adding that money to your upgrade budget. That is, if you want GeForce 6600 graphics, don't start with a Dell Dimension 1100.