There are two kinds of people who download software -- those who have picked up a virus or other computer infection, and those who will. You need to be very careful to put it off as long as possible. I've downloaded and installed scores of programs but so far none have bit me. [a few of them]
Commercial: Mainstream software offered for download by big companies. Some is even free or free for home use. Most of it is priced in the "boxed software" range. The same software is usually available in stores as well as online.
Freeware: Some freeware rivals the capability of commercial software, but usually it's smaller programs developed by individuals or shareware developers. Warning: freeware can be addictive -- it's free -- easy to download -- often excellent -- and there are thousands of programs to try. :-)
Many freeware programs are superb, but a few are written poorly. Freeware can also conceal "spyware", viruses or Trojans and other parasites. Avoid problems by using your common sense and by following the rules for safe downloading listed below.
Shareware: Usually modestly priced, intermediate in size and closer to commercial software in features. Some shareware is the best software written. The usual price range is $10 to $30. Often there's both a freeware and shareware version of the same software. The freeware version may run ads and/or limit functions. Shareware can often be used for 30 days or so on a free trial basis. After that time it will shut down unless you buy a registration code to keep it working.
Updates & Extensions: "Filters", "codecs", "modules", updates, etc., that augment or revise the capabilities of Windows and other programs, mostly browsers. They're usually free, and they are often offered when you click a link that won't work without the new software. They're often needed by Multimedia programs like Windows Media Player and RealPlayer. Be very sure the site is trustworthy before you proceed though.
SiteAdvisor is a new service that checks websites for suspicious activity. SiteAdvisor helps protect you from all kinds of Web-based security threats -- spyware, adware, spam, viruses, browser-based attacks, phishing, online fraud and identity theft. Note: SiteAdvisor does not protect against Phishing, as that is a different kind of attack.
These major download sources are trustworthy. They usually have ratings of the programs (often written by the supplier however). Check a with a couple of them to compare notes.
Tucows :: MajorGeeks.com :: WebAttack :: NoNags :: Jumbo! :: Pricelessware :: WinPlanet :: ZDNet Downloads :: CNET
I created some special search engines that you can use to find programs at trustworthy sources.
You'll find over 5000 programs at Microsoft's Free Downloads Center. Lots of games, but many other programs as well. The Ultimate List of Windows Software from Microsoft may make it easief to find what you want.
Warning: Download managers, Zip programs, and of all things, anti-spyware programs are often used as bait for adware and spyware. Don't forget the "rules to download by" when you're considering one of them.
I no longer use a special download manager. Firefox has a built-in download manager. It lets you save the files where you want (set up in options), download multiple files at the same time, and easily pause and resume any download. That's good enough for me. :-) I also follow a process to keep my downloads well organized. ;-)
Ed Bott suggests a simple but effective way to keep track of not only downloads, but the essential information that goes with them.
http://www.edbott.com/weblog/?p=693 -- getting them organized
http://www.edbott.com/weblog/?p=1254 -- keeping them organized
If you do a lot of downloading, especially on dial-up, you might appreciate a download manager. They let you pause downloads, and resume interrupted ones without losing the part you've already downloaded. They'll also help you keep track of the files you download. [free download managers]
Windows XP handles Zip files as "compressed" or "zipped" folders. You can view the contents just like a regular folder. You can make compressed folders work almost as well as a Zip program. [Click Start > Help and Support > enter "zip", "zipped" or "compressed" (without quotes) > click the green arrow.]
If you run Windows 98, or just don't like the way XP does things, you need a Zip program. I recommend UltimateZip [no longer freeware] or WinZip. Don't just pick any old unzip program -- many of them harbor spyware. There are some good free ones out there though.