For some advanced Windows system utilities try the Sysinternals tools.
Notepad++ is one of the best free text editors available for Windows.
The free version of NoteTab is an alternative.
IrfanView has got to be top of the list for Windows.
More power required? Switch to OS X and use Acorn (paid).
Filezilla for both Windows and Mac.
Web hosting and domain registration
I've used UK Servers Ltd for several years now via their website VirtualNames. They have provided all the services I've required to run a number of websites plus superb technical support when (rarely) needed.
Antivirus and malware removal
Using Windows I'm now happy to rely on Microsoft's antivirus solutions - MS Security Essentials on Windows 7 and the built-in Windows Defender on Windows 8/10. They have evolved a lot in the last few years and personally, with due care and awareness about what I'm doing online, I don't think it's necessary to pay expensive subscription fees to other companies.
For malware removal see this dedicated page.