I would like to talk about 10 software tools that I believe every computer and network technician should carry at all times. I am going to keep this current, so I am going to assume you have a USB thumb drive with plenty of space to store and keep these software tools.
Here are the following 10 software tools every computer/network tech should have:
1.) CCleaner - This is one of my favorites and I keep a portable copy on all of my thumb drives. This tool is great for cleaning up all the muck that accumulates on a average PC. CCleaner boasts many features. It has very thorough cleaning options, a registry cleaner, startup/system restore utilities & uninstaller utility. It even includes a drive wiper with DoD, NSA, and Gutmann wipe capabilities! It truly is a wonderful all-in-one utility to have handy. Available as an install or portable version.
2.) Defraggler - Another fine product from Piriform. By this time I am probably starting to sound like a fan boy of their products, but truth be told, I am. I have been using and recommending them on a regular basis for years now. This defragger seems to do a much better and quicker job than what is built in to Windows. Give it a try, it's available both as a install and portable version.
3.) Over-look Fing - If you were a user of Look@LAN, you need to download this newer version. Fing is a very powerful free network discovery utility. However, it does not have a GUI yet, it's all command line. Install and configuration is very easy, and info is gathered quickly. If you are a Android or iPhone user, there is an app available for those platforms that work well. If you are tasked with performing a site survey or trying to track down a service port running on a node, or just curious, this tool is for you.
4.) Notepad++ - Notepad++ is a great text and code editor that is available as an install or portable utility. I have used this app multiple times to inspect hosts files, make changes to config files, build scripts from scratch or to just take some notes on the go. It supports multiple languages and is governed by GPL license.
5.) Ubuntu Linux - I can't begin to explain how useful a copy of Ubuntu Linux is to have on a USB thumb drive. I tend to carry the latest version with me as much as possible to use in copying files from a dead windows system before reloading it or just using the live version to quickly run some tests that can't necessarily be done with Windows running. It's very easy to create a bootable USB drive with Ubuntu loaded. Check around, there are pre-made ISO's that have targeted tool sets on them.
6.) Memtest86 - Great utility for testing memory modules for errors. Windows 7 has a utility built in and it works great as well, but I like to use at least two tests on memory. I taught a younger co-worker today how to used both of these utilities and pointed out how sometimes you may get false positives from one utility, but another will find no problems. Windows failed the memory test on the extended portion of it's test, Memtest86 ran 3 passes with no errors. Memtest86 has more options to do more targeted tests. Available as an ISO, or bootable USB install.
7.) Secunia OSI - Secunia Online Software Inspector and Personal Software Inspector (PSI, the installable app) is a great tool to check a system for outdated or un-patched software. The newest version scans rather quickly and provides direct links to the vendor's patches while showing you any end-of-life applications that may be lurking on a system. I used this utility quite often, and it's a real eye-opener. I highly recommend using it. OSI can be made an internet shortcut on your USB thumb drive.
8.) Check Lists & Documentation - I preach this all the time to clients and co-workers. This is the part of the job that is the most difficult to start and keep current at the same time, I know, I struggle with it myself everyday. It is very important to keep up to date check lists if you are regularly performing duties that you have to report on and documentation for when you need to make a change to a computers software settings or network configurations. This can be a simple text document that you keep using the aforementioned Notepad++ or a complex spreadsheet or web-based help desk. Carry the shortcuts or documents you need on your USB thumb drive and be sure to back them up regularly. It's a real time saver.
9.) Drivers - I find myself imaging quite a few systems from time to time and troubleshooting the same type of hardware. Every now and then I have to reload a network card driver. As you probably have guessed, that usually means no internet access and a trip to another computer. This is a waste of time. Carry the most common drivers you encounter (mine are Intel Pro100VE and Realtek RL8139 NIC's) that sometimes are not detected by Windows. This is another thing you may want to periodically check for updates and keep the most updated version handy for those types of situations.
10.) Portable Apps - If you don't need to boot to a live version of Ubuntu, but want to use a set of personalized apps, I recommend checking out this site. Lots of common applications ported to USB thumb drives for on-the-go use. Lot's of great apps and I also use this software often. It's easy to install and works well.
Well that's it for my 10 Tools list - Software Edition. These are just tools I have used the most in the time I have spent in the field and have found to be the most reliable and useful. There are many other utilities out there and I recommend trying them all to find out what works best for you.