WinRAR is a powerful archive manager. It can backup your data and reduce the size of email attachments, decompress RAR, ZIP and other files downloaded from Internet and create new archives in RAR and ZIP file format.

In almost every post from sys.tools i see comments like "Sanboxie this", "Sanboxie that"... Honestly, i never used it. But i always had one on my backup.
my advice to those who don't know about Sanboxie is this: at least understand how it works, so you'd now when you need it.

"Sandboxie runs your programs in an isolated space which prevents them from making permanent changes to other programs and data in your computer."

UPD: Team EAT released x64 version.

enough for freewares... this one is not a "must have" and i don't use it often, yet it's the best tool for monitoring your hard drives.

I won't argue with anyone nor explain why;
This is merely my choice of utilities for fine-tuning my system.

foobar2000 is an advanced freeware audio player for the Windows platform.
Some of the basic features include full unicode support, ReplayGain support and native support for several popular audio formats.

it is obvious that many musicians use multiple monitors;
while Windows has very poor support for that, UltraMon will gives you everything you need to work with 2 and more monitors 100% efficiently.

if you using multiple monitors, you must have UltraMon in your startup!

UltraMon is a utility for multi-monitor systems, designed to increase productivity and unlock the full potential of multiple monitors.

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there was a time when i wanted to have two similar OS on one HDD: one for music, and another for design (with local server and other crap).
and this is the tool that helped me to do that and much more.

EasyBCD is NeoSmart Technologies' multiple award-winning answer to taking control of your bootloader. EasyBCD extends and revamps the Windows Vista/Windows 7 BCD bootloader, and with EasyBCD, almost anything is possible. Setting up and configuring a dual-boot between Windows 7, Windows Vista, older versions of Windows such as XP & 2003, Linux, Ubuntu, BSD, and Mac OS X is a breeze. You just point & click and EasyBCD does the rest.

EasyBCD is geared for users of all kinds. Whether you just want to add an entry to your old XP partition or want to create a duplicate for testing purposes; if you're interested in debugging the Windows Kernel or septuple-booting your seven test operating systems, EasyBCD is the key.

Treesize is a small freeware utility that is a real must to discover how your system (stupidly) allocates your files and where you're wasting space with your libraries. It's incredibly small, light and fast and integrates without problems with explorer.

I've been using this for ~8 years.. one of those programs which i'm ready to pay for, but it's free

doesn't matter what you do on your computer.. we all have photos and graphics on our drives, so i'd say this is a must have for everyone.
the only decent alternative is ACDSee, but it's not even close to XnView's simplicity and usability.

Come to discover XnView, a software to view and convert graphic files, really simple to use! Support of more than 400 graphics formats! It's free, so do not hesitate!

Freearc is definitely the best and fastest lossless compressor and lets you save a lot of space on your hard disks. It beats easily winrar and many times it is even stronger than 7zip.

But the real interest for this forum on this software comes from its ability of compressing using many different algorithms, among which there'a a very powerful and incredibily fast WAV compressor, that allows to save a lot of space and time in storing your own uncompressed wav libraries.

Definitely worth having tool for monitoring your hardware.
I just noticed that they have PRO version which supposed to give you controll of fans speed.. that should be even more awesome!

...remember the saying "best software always free"?

don't want to talk much about this one... it's simply the best passwords manager!

can't describe how much i love autoruns!
i use it to control services, edit context menus, manage programs autostart (obviously)...

another tool you definitely should have!

this will be the first post in my section sys.tools, where i shall share "must have" appz for managing your Windows.
because unfortunately, that where most of us stuck...

Process Explorer is a replacement for your standard Task Manager, was developed by Sysinternals a long time ago, and later bought by Microsoft.
since then, everybody who used Process Explorer wondered why Microsoft wouldn't just replace their Task Manager with this one...
anyway, i would say it is a must have.