How You Can Improve the Speed of Vista machine?

Vista is about looks. Every one of those effects, from the translucent windows to the pearlescent shine to the oversized icons, eats up processing power that would otherwise be spent on running applications.
Also, much of the new software that comes on a pre-built computer (i.e. the "free" antivirus, AIM, other mfg. programs) are also serious resource hogs. Norton's AV products have been getting worse and worse each year, to the point where they can cut the system's performance in half.

The best handful of "tweaks" you can make to your Vista system to speed it up are as follows:
(Note: You can access the first three of these options by going to Control Panel's Classic View, then clicking Performance Information and Tools.)

1) Change the Theme: By going into Adjust Visual Effects and unchecking things you can do without (you may want to play around to see how you like it), you can remove all of the resource-sucking features of Vista.

2) Disable Indexing: One of the not-so-new features of Vista is the Indexing Service, which quietly catalogs your computer in the background to make searching faster. Problem is, it uses a lot of resources for (IMHO) a not-so-useful function. Yeah, it helps speed up your searches, but it's not worth the performance sacrifice.
You can disable this by going into Adjust Indexing Options, clicking modify, (clicking Show All Locations if applicable) and unchecking everything.

3) Ditch the Bloatware: All that junk that your computer comes with slows it down. By going into Manage Startup Programs, you can stop them from starting with your computer. Leave all the Microsoft Stuff alone, and disable the others that you don't need. If something doesn't work right after reboot (i.e. no Sound or lousy Graphics), you probably disabled a driver. Just go back in and turn it back on. (Granted, this is a little more dangerous than the other options, so exercise common sense here. We don't want to make things worse.)

4) Scrap your Slow Security Software: If you're still using the "free" Antivirus / Security Suite that your computer came with, you might want to consider something else. While I realize I might get flamed for saying this, I recommend something like Windows OneCare or Webroot's Antivirus for their small performance footprint and "set-it-and-forget-it" ease of use. Plus, OneCare can be used on two other PCs, too.

5) Don't be a Packrat: This one is probably the hardest to stick to, but also the simplest solution. Don't install programs you don't need, keep your documents folder organized, and keep the desktop as clutter-free as possible.

Now click "Update my Score" and watch your performance ratings soar!