XP Slows down after one hour

Are you always connected to the Internet? Are you running Kazaa or any of the programs that "take control" of resources? Did you turn off the Restore Point functionality of WinXP? Do you regularly "maintain" your OS (clear ~*.*, *.tmp, Temporary Internet Files, c:\winnet\prefetch etc.) and run a scandisk and defrag? Have you used Ad-Aware to find out if there are any spyware and/or other tojans on your computer ( http://www.lavasoft.de/support/download/ ) ?

Ultimately, there are many factors that play into WinXP and how it will continue to operate after use for awhile.

Here's a list of XP Speed tweaks you might want to run through:

http://datacreek.net/webgear/tips/xptweaks.html

. Windows services
Many Windows services are enabled by default. Many of these services, however, are not required for your machine to run properly. You should review the services running on your Windows 2000/Windows XP computer and disable those that you don’t need.
One way to see what services are running is to use the Services applet found in the Administrative Tools menu. Right-click My Computer and select Manage. Important information contained in the Services console includes the service Name, Status, and Startup Type. You can get more details on a service by double-clicking on it to bring up the service's Properties.

You can stop the service by clicking the Stop button. If you are sure that you don’t need the service, click the down arrow in the Startup Type drop-down list and set the service to Disabled. If you are not sure if you need the service, change the Startup Type to Manual. Then you’ll have the option of manually starting the service if you find that you need it.

Another way of controlling which services start is using the msconfig utility. Open the Run dialog box and type msconfig in the Open text box.

Notice the Essential column. These are services Microsoft considers essential torunning the computer. However, note that many required services are not defined as essential in the System Configuration Utility window. You can prevent a service from starting at bootup by deselecting the check box to the left of the service.

One service that is well known for slowing down Windows 2000/Windows XP systems is the Indexing Service. This service indexes the content of each hard disk and makes it easier for the Search utility to find files. Unless you are running a Web site thatuses the indexing service, you may want to disable it to improve performance.

You have used this computer for a long time? If so, it may be caused by the following:
a) index of files: solution: "defrag" frequently.
b) too much services (which is unwanted); there are lots of services automatically opened by XP. check them and disable some.
c) software problems: some software will eat lots of RAM or you have opened too much software together.
d) Internet: software: e.g. edonkey will eat tons of RAM / some softwares are buggy and will slow the computer: what is the lastest installed software. Virus attack /trojon / or others; use virus scanner and AD-aware to check the trojans.
e) Sometimes wrong with the hardware? overheat of the CPU (few occassions; but will poor tower case or conv..)

You have used this computer for a long time? If so, it may be caused by the following:
a) index of files: solution: "defrag" frequently.
b) too much services (which is unwanted); there are lots of services automatically opened by XP. check them and disable some.
c) software problems: some software will eat lots of RAM or you have opened too much software together.
d) Internet: software: e.g. edonkey will eat tons of RAM / some softwares are buggy and will slow the computer: what is the lastest installed software. Virus attack /trojon / or others; use virus scanner and AD-aware to check the trojans.
e) Sometimes wrong with the hardware? overheat of the CPU (few occassions; but will poor tower case or conv..)

You have used this computer for a long time? If so, it may be caused by the following:
a) index of files: solution: "defrag" frequently.
b) too much services (which is unwanted); there are lots of services automatically opened by XP. check them and disable some.
c) software problems: some software will eat lots of RAM or you have opened too much software together.
d) Internet: software: e.g. edonkey will eat tons of RAM / some softwares are buggy and will slow the computer: what is the lastest installed software. Virus attack /trojon / or others; use virus scanner and AD-aware to check the trojans.
e) Sometimes wrong with the hardware? overheat of the CPU (few occassions; but will poor tower case or conv..)

I had the same symptoms on a brand new XP except that in our case it would slow down to molasses speed after about 1/2 hour. The following is my notes on the issue, hopefully it is what resolved the problem:

Regedit HKLM\system\currentcontrolset\services\lanman\workstation\parameters
Changed Enable Security Signature from 1 to 0

(note: be sure to make a backup of your registry before making any changes) Hope this helps.