I recently installed a new HD and added 512mb ram and Vista to a Dell Dimension 2400. Boots up very very slow and to try and start a program is so slow. I don't even want to try to connect to internet yet, it would be a joke. Help please.

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Well for starters you should be running Vista with at least 1 GB of ram, 2 GB for optimal performance, but since your motherboard doesn't allow 2 GB of ram then 1 GB of ram is all you can do. Anything lower then 1 GB of ram and you are really going wish you were using XP. You say you installed 512mb of ram, plus the intergrated graphics processor you have in there is sucking at least 32mb away from your main system ram if not more which is only leaving you atleast 480mb of system ram left. This is why Vista is running like garbage on your pc. Since your motherboard only has regular PCI slots you are very limited in graphics card choices, but they do still sell PCI graphics cards. You can pick up an Nvidia 6200 PCI graphics card cheap from newegg.com which should help a lot to improve performance over the intergrated graphics porcessor that you are running in your system now. Not to mention will have it's own ram on the graphics card so it won't be sucking it from the system ram like the intergrated graphics processor is doing. Adding 1gb of ram and a graphics card like i mention will be a nice size improvment over what you have now and Vista will run a heck of a lot smoother and faster. Iron Sharpens Iron.