It depends, I mainly use hitmanpro usually daily but sometimes i'll use mbam or eek and I may even use killswitch once in awhile.
I rely on my AV to do the heavy lifting, my firewall is a nice complement, and I run weekly scans with MBAM.
Real time and On demand scans. Additionally i check the HIPS rules every now and then. Used to do some tweaks to Windows in Windows 7, have not done anything in Windows 8 yet.
Real time, on demand, killswitch and comodos file scanner on Win7 and XP. Tweezers,cotton buds, mirrors, petri dishs, miroscope, metal detectors, x-ray machines and body scanners on myself.
If I have a reason to suspect a problem, I run an integrity check of all the files in the Windows directory, all of its subfolders, and everything in Program Files. I also create a complete filelist of everything on the system drive and compare it to an existing file list that's kept in encrypted storage. If I'm still suspicious after that, I boot to an alternate OS, create a new file list from there, then compare it to the list created from within Windows. This will expose any hidden files. If I suspect unwanted changes or additions to the registry, I restart the system. My entire registry is replaced by a clean, optimized copy on every reboot.
Your security solutions are just way beyond of what I can comprehand right now But how often does you Windows 98SE actually get infected? I assume that nobody makes malware for older Windows anymore so it can't be much.
Integrity checkers have been around since Win 95 or earlier. They create hashes of the files or folder contents that you select. When you run it again, it repeats the process and compares the new hashes to the previously made ones. If the file hash changes, the file has been changed. This is best suited for executables, DLLs, config files, etc. The file hashes do need to be recalculated after system updates, new installs, etc. File lists work in much the same way except that more of the process is done manually. You make a list of everything on your system from a command prompt. When you want to check, you make a new list and use a comparison tool to highlight the differences. Rootkit infections can hide files from Windows and tools run from within Windows. By comparing lists made from within Windows to ones made from another OS, you can see files hidden by rootkits. On 98 systems, you already have that 2nd OS, DOS. You can also use a separate XP or linux system or a live CD. These methods work the same on any OS. The only things that change are the files that you keep tract of and where they're located. They're best suited for systems that don't change much. The more you install, remove, update, etc, the harder it gets to keep the hashes and file lists accurate and up to date. It also helps a lot if you put your operating system and data on separate partitions. AFAIK, my system has been compromised twice, both times in 2004. The first was a virus that crashed Norton Internet Security. The second time I was hacked. Norton Internet Security logged the entire event, including giving executables internet access and did nothing to stop it. Needless to say, that was the last time I used anything Norton/Symantec Almost nobody directly targets 9X systems any more, 3 letter agencies not included. That said, a significant percentage of malware will run on any version of Windows. A growing percentage of malware targets user applications like the browser. If that malware is intended to steal credentials, credit card info, etc, or is to just de-anonymize you, the OS you're using won't matter nearly as much as which browser you're running and how you have it configured and protected.
