System Monitoring and Information Tools

IceSword Free
IceSword is delete-enforcer, not really System Monitoring but it's a way of force-deleting files and such, this program combined with Process Explorer and Autorunsis a great way of removing spyware/malware.

Autoruns Free
Autoruns is simply a check up program on what processes or files are ran automatically by the system, a great tool when removing spyware and such

Sysinternals Process Explorer Free
Process Explorer is a system monitoring and examination utility and can be used as the first step in debugging software or system problems when in the hands of an experienced software engineer.

Sysinternals Process Monitor Free
Process Monitor is an advanced monitoring tool for Windows that shows real-time file system, Registry and process/thread activity. It combines the features of two legacy Sysinternals utilities, Filemon and Regmon, and adds an extensive list of enhancements including rich and non-destructive filtering, comprehensive event properties such session IDs and user names, reliable process information, full thread stacks with integrated symbol support for each operation, simultaneous logging to a file, and much more.

Process Guard Trial
Basically tells you what every file is doing when it does it, and whether or not it should allow it. At first it can be annoying, until you set certain files' permission. After that, if you ever have a program doing something it shouldn't, it will tell you. If something is starting something else up, closing something, accessing the registry, etc, it will tell you. It can also stop keyloggers/rootkits/many other things. Very nice, but requires user input.

GPU-Z Free
GPU-Z is a lightweight utility designed to give you all information about your video card and GPU.

CPU-Z ---- Alternate download Free
CPU-Z is a freeware that gathers information on some of the main devices of your system.

WinDirStat Free
WinDirStat shows a graphical representation of all files on the drive you scan, and you can delete any unwanted stuff.

Hijackthis Free
A general homepage hijackers detector and remover. Initially based on the article Hijacked!, but expanded with a lot of other checks against hijacker tricks. It is continually updated to detect and remove new hijacks. It does not target specific programs/URLs, just the methods used by hijackers to force you onto their sites.
As a result, false positives are imminent, and unless you are sure what you're doing, you should always consult with knowledegable folks before deleting anything.

SpeedFan Free
If you need a tool that can change your computer's fan speeds, read the temperatures of your motherboard and your hard disk, read voltages and fan speeds and check the status of your hard disk using S.M.A.R.T. or SCSI attributes, then you came to the right place. SpeedFan is the software to go. It is fully configurable and you can create custom events to handle every situation in an automated way. SpeedFan works under Windows 9x, ME, NT, 2000, 2003, XP and Vista. SpeedFan works fine on Vista 64 bit too. The relevant driver is now signed with my digital certificate. And this all costs you absolutely nothing!

CPUInfo Free
CPUInfo provides quick verification of key system parameters such as processor speed, model number and cache settings. CPUInfo is a 'no install' program, just download cpuinfo.exe and run to see your results. No installation is required.

Auslogics System Information Free
Auslogics System Information provides comprehensive and easy to understand information about your system configuration. It can show hardware configuration, video-card information, OS details, list of running processes and other information. This program is FREE.

Motherboard Monitor Free
Motherboard Monitor (MBM) is a tool that will display information from the sensor chips on your motherboard in your Windows system tray. MBM supports a wide range of Chipsets & Sensor Chip combinations. It can sense temps from Cpu, HDD, GFx and Mobo. It does also sense Fan speeds. If it senses that your hardware is overheated it can protect it by Shutting it down (user configured)

CoreTemp Free
Core Temp is a compact, no fuss, small footprint program to monitor CPU temperature. The uniqueness of it is that it shows the temperature of each individual core in a each processor in your system! You can see in real time how the CPU temperature varies when you load your CPU.