Is your machine always “just poking along”? Do you know which of your running programs are RAM hogs? Do you still have DLL’s running in the background when they’re no longer needed, and they seem to take forever to unload??
Unfortunately, in many cases, Windows fails to correctly unload programs and DLL’s from memory (RAM) on program exit. So less memory is available for new programs; this can cause excessive system slowdown, or in some cases system crashes. FreeRAM XP Pro will free up and optimize memory, allowing your computer to perform to its optimum level.
This free utility includes automatic memory monitoring and optimization, advanced tray support, fast, threaded freeing with a stop option, multiple system-metric monitors, a simple and attractive GUI, memory reporting and diagnostic logging, and real-time memory information.
The program’s AutoFree feature intelligently scales how much RAM is freed with your current system status, so that RAM is optimized without slowing down your computer.
FreeRAM XP Pro has been designed to be easy to use, yet highly customizable by computer novices and experts alike. Despite the fact that I have 1 GB of Ram, I have used this neat little utility for a number of years, and I have always been impressed with its performance.
Fast facts:
Automatic, real-time memory monitoring and optimization
Fast, threaded memory freeing with stop option
AutoFree option intelligently optimizes RAM without sacrificing performance
System metric and performance monitors
Advanced tray support
Memory reporting and diagnostic logging
Simple, attractive interface
RAM-cuts (RAM-freeing Windows shortcuts)
Customizable Windows hotkey support
Access to Windows memory-related tweaks that could enhance system performance
Process memory usage reporting
Unique memory compression technology directly reduces applications’ “working set” memory requirements instantly and without swap file usage: completely unlike other memory programs
Requirements: Windows 95/98/Me/2000/XP/2003 Server
Download at: Download.com
Bill Mullins' Weblog - Tech Thoughts 
Microsoft has, for the most part, remedied RAM operations with Vista.
On my XP Pro machines (and folks, if you’re running an older version of Windows than XP, please rethink) I found that this tool does what it advertises, and is set-it-and-forget-it simple.
It didn’t turn my machine into a speed demon, but it did elimate the slow down, and practically eliminated all the “(Program Not Responding)” wait periods.
Thanks, Mr. Mullins. When I see you recommend a program, I know you’re describing a Best of Breed.
I had tried few different RAM optimizers in the past and not once I felt that they actually do something.
My home PC (XP SP2) is always on with normal uniterrupted uptime of 30-40 days (sometimes I just have to install something requiring reboot, etc). Most of the apps start once and just keep running. And I have no memory problems.
My opinion that people are looking for leaks in the wrong place. Windows is pretty good at what it does, it’s crappy software that can leak resources.