I've seen alot of links to many of these free security software programs here on AO and discovered a very helpful compiled list on PCWorld.com. I'll post a few of the the links here, if you'd rather just go to the site itself, I'll post a link to that as well. (some of these links are older and/or are applicable to specific OS's) There are other programs as well, just check around, see if anything applies. I also recommend sorting by date, you'll find some other cool downloads (more recent).

Ad Aware
Rid your system of advertising spyware with this freeware utility.
[Free][Windows 9.x, Windows Me, Windows 2000, Windows XP, Windows NT]

Zone Alarm 3.1
Get protection for DSL and cable connections with this free utility
[Free][Windows Me, Windows 2000, Windows XP, Windows NT, Windows 98]

Sygate Personal Firewall 5.0
Secure your sensitive files from invaders both inside and outside your network
[Free][Windows 9.x, Windows Me, Windows 2000, Windows XP, Windows NT]

Bugnosis
Be alerted when Web bugs attempt to track your surfing.
[Free][Windows 9.x]

PassKeeper
Keep all of your site registration information in one place
[Free][Windows 9.x]

BoDetect 3.5
Remove Trojan horses, and alert yourself to software on your system that monitors you
[Trial] [Windows 9.x]

Tiny Personal Firewall
Allow your PC to selectively receive data from the Internet
[Free][Windows 9.x, Windows Me, Windows 2000, Windows XP, Windows NT]

NetWatcher
Monitor cookies and other requests for information that attempt to reach your PC
[Shareware][Windows 9.x, Windows Me, Windows 2000, Windows NT]

Password Pal
Manage all your passwords
[Free][ Explorer 3.0 or higher, or Win95 OSR2]

Surf Secret Deluxe
Cover your tracks with this browser-cleaning utility
[Trial][Windows 9.x, Windows Me, Windows 2000, Windows XP, Windows NT]

CmosPwd
Find and reset your CMOS password
[Free][Windows 3.x, Windows 95, DOS]

007 for Win 95/NT
Password-protect your programs
[Shareware][Windows 95, Windows NT]

Norton Internet Security 2002
Protect your PC from Internet-borne threats, control cookies, and block pop-up windows
[Demo][Windows 9.x, Windows Me, Windows 2000, Windows NT

Whisper 32
Access your protected applications with this free password manager
[Free][Windows NT, Windows 95]

OuttaSight
Hide any active window, taskbar item, or system tray icon
[Shareware][Windows NT, Windows 95]

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