Downloads (all free!)

CCleaner cleans up junk and temporary files, also secure erase
Defraggler free defragmenter – works better than Windows Defrag. Do not use on Solid State Drives.
CheckDiskGUI – provides an easy interface to chkdsk, to check for and repair errors on your hard disk. Do not use recover mode on Solid State Drives.

Open Shell Menu essential for Windows 10, 11 (and 8) – get your Start button back!
Adobe Reader essential for viewing PDF documents (do not download extra junk such as McAfee)
Office 2007 Compatibility Pack for opening Office 2007 and 2010 files in earlier versions of Office.
Bonjour Apple’s Bonjour Print Services for Windows
Powerpoint Viewer from Microsoft

MalwareBytes for removal of spyware. I like the free version but you need to remember to run it yourself. The Pro/Premium version is always on the lookout. You may try the trial and revert to the free version at the end of a month.
MalwareBytes BrowserGuard is a free browser extension that blocks ads, tracking cookies, scams, malware and dangerous websites.

BackBlaze – Online backup – great value for about $5 per month. Full disclosure: this link gives me a teeny tiny commission. Carbonite is also good.
Keyfinder records your Windows and Office license keys in a text file.
Asterisk Key reveals the password behind the ***.
Spybot also for removal of spyware
SyncBack “Synchronize & Backup”
File Shredder to securely delete files from a hard drive – but CCleaner can also do this.
VNC remote control assistance

iTunes free music player from Apple
Picasa free photo organizer and editor from Google
OpenOffice.org free replacement for Microsoft Office!
Roboform for securely storing online passwords (only free for a certain number of passwords)
Firefox web browser replacement for Internet Explorer
Google Chrome a fast browser. Works especially well on older, slow computers

Use them in this order:

rkill attempts to terminate known malware processes so that your security software can run and clean your computer of infections (click the green “Download Now @ BleepingComputer” button)
TDSSKiller Root-kit remover (fast, but more limited. Click “TDSSKiller.exe” in the section titled: “How to disinfect a compromised system”. )
JRT (Junkware Removal Tool). Works as advertised. (click the green “Download Now @ BleepingComputer” button)
AdwCleaner – my favorite, but always requires a reboot. Check what folders it wants to delete because once or twice is has wanted to delete an important folder. (click the green “Download Now @ BleepingComputer” button. Alternatively click “Visit Author’s Site” for the latest version).
ComboFix Root-kit remover (click the green “Download Now @ BleepingComputer” button). Doesn’t work on Windows 10 yet nor on newer versions of Windows 8.
autoruns – to see what programs (viruses?) are starting up.
sometimes what looks like a virus can be something as simple as a start page change or a command embedded in an shortcut / icon to open a certain site. These are easy to check and fix.
HijackThis – if you’re still having trouble. Handle with care.