I am a computer tech of 10years, mainly fixing and building home PCs. I have the following suggestions.
1. Be sure you have a good Anti-Virus program installed. I recommend Avast Home (free).
http://avast.com/eng/download-avast-home.html
Avast Home is free with registration. I register w/ a hotmail account so it gets spammed rather than my main email account.
2. Be sure you have a good Anti-Spyware program installed. I recommend Spybot (free).
http://www.safer-networking.org/en/download/index.html
Be sure to run it and do the immunizations to help block attacks.
I don’t run the TeaTimer portion or the Homepage monitor parts; they just eat up ram when I am clean.
(I recommend a thorough scan of each once a month; just start the scan before you head out for a few hours)
3. PC Wizard 2008 (free) will allow you to answer questions people ask you about your hardware.
http://www.cpuid.com/pcwizard.php
PC Wizard 2008 can monitor CPU usage and run general benchmarks.
To post your hardware configuration here do the following
A: Install PC Wizard 2008 and run it.
B: Click on the System Summary icon under Hardware (looks like a computer & monitor). You will then see the summary in the right window.
C: Put your cursor on the Mainboard line in the right window and click the right mouse button and choose Select All
All lines of text should turn blue.
D: Right click on the Mainboard line in the right window again and choose Copy.
E: You can now paste the entire system summary into a text file or a Post on this site so we can better help you.
Here is what my System Summary looks like using PC Wizard:
Mainboard : Asus P5ND2-SLI
Chipset : nVidia nForce4 SLI Intel Edition
Processor : Intel Pentium XE 830 @ 3000 MHz
Physical Memory : 2048 MB (2 x 1024 DDR2-SDRAM )
Video Card : Nvidia Corp GeForce 7800 GT
Hard Disk : NVIDIA (500 GB)
DVD-Rom Drive : AOPEN DUW1616/ARR
Monitor Type : Dell Computer DELL 1905FP - 19 inches
Monitor Type : Planar PL1700 - 17 inches
Network Card : Ralink Technology Corp Ralink RT2500 802.11 CardBus Reference Card
Network Card : Intel Corporation 82540EM Gigabit Ethernet Controller
Operating System : Microsoft Windows XP Home Edition 5.01.2600 Service Pack 2
DirectX : Version 9.0c (May 2007)
Note: it IS possible for some of the newer CPUs to clock down to half speed during low usage to save on the electricity usage and to lower the CPU temperature. Slowdowns don’t have to be because of CPU usage, an example is when you are low on RAM (or your RAM is eaten up by a virus).