A lot of people will experience a day when your new fast computer gets slow. This happens for a number of reasons and I will explain the two most important ones briefly.
1) When you have a new computer it usually comes with very little programs installed to take up your RAM memory, as you install more programs they load automatically on startup. Eventually, you have so many programs loading on start-up that your memory gets used up making the computer run slow. You fix this by first disabling unwanted Startup Programs and then by adding more RAM to your computer. This step is the biggest performance gain in any PC Tune-Up.
2) The other obvious problems that come up are junk programs, viruses/spyware, hard drive fragmentation, and temporary internet files. These things clutter the hard drive and consume resources that windows needs to run fast and efficient.
Viruses and Spyware can actually delete files and destroy an install of Windows so its extremely important to clean those off. These things can be cleaned out and I will cover how to do this below:Doing a Computer Tune-Up For Windows XP / Vista
1) Go to Google and search for crucial memory. Visit their site and run their memory scan tool. It will analyze your memory and suggest upgrades you can do to your exact computer model. In most cases the cost will be around .00 to .00 dollars for the parts. Ideally, you want your computer to have a minimum of 1GB, but 2GB is highly recommended. Especially if you have Windows Vista.
2) The second thing you do is to modify your startup items by using "MSCONFIG". You can access "MSCONFIG" by going to your Start Menu and selecting Run. Then in the command line type: "MSCONFIG". Go the start-up tab and you can then deselect certain items from starting up. I like to reference the command line and just look at the path of the item. That will give you a good idea what program it relates to and if you need it starting up or not. If you are not sure of the item enabled then you'll need to research the name on GOOGLE or just leave it alone.
3) The next step is to access add / remove programs in your Windows Control Panel. Go through that list and look at the programs installed. Only uninstall programs you don't use anymore. Especially the big ones taking up lots of hard drive space! If your unsure of an item then leave it alone or research the item name on GOOGLE.
4) After that you can access the disk clean up utility by opening up "My Computer" and right clicking your C drive and selecting properties. Select the disk clean up utility and it will take a few minutes to scan your hard drive. After that, it will have you select different types of files to clean off. I normally select my Downloaded Program Files, Temp Internet Files, Recycle Bin, and Temp Files. I don't recommend compressing old files so I usually leave that option unchecked. Everything thing else should be unchecked unless you want to perform that action. After that let it run until it finishes.
5) At some point everyone needs to defrag there hard drive. This will increase the speed at which your computer accesses data from the drive by reorganizing the data bits closer together. As things get installed and removed from the system the drive will become fragmented, so this will reverse that process! You can access it from Start Menu / Programs / Accessories / System Tools / Disk Defragmenter. When it launches just select your drive, then hit defragment. If the drive does not need to be defragged then it will tell you after its initial scan.
6) Virus and Spyware removal. If you don't have a good Anti-Virus software installed then I would install AVG free 8 on your system. You can download it from AVG's website, just Google free avg basic.
Follow the instructions for downloading and install. It will provide you with all the protection you need for viruses and spyware. Another excellent utility for spyware removal is a utility called Spybot. You can download and install it from here: http://www.safer-networking.org/en/download/index.html
In conclusion if you have followed all of these steps and your computer is still having problems freezing up or is running very slow then you need to rebuild windows and backup your data. I have followed this plan before on many of my customers computers and it shows dramatic increases in speed most of the time. But sometimes if the computer is badly damaged from a virus or its more than three years old its just time to either do a fresh install of windows, or buy a new computer!