The OS works and does what we want it to do, so we don't want to upgrade, please understand this.
Same here NightShade, (OS ME) Just read the problems the other OS Systems are having right here. I will really miss mine when it will no longer be able to run.
The problem is not 'the OS does what you want it to do' but what it 'can't' do in relationship to avast (and many other applications). avast! want to make changes to better protect the majority of systems. Already some of these improvements don't work in win9x/winME, but fortunately they are able to be discarded in older OSes.
The problem comes when avast wants to make changes in the core functionality of avast that isn't supported in older OSes and this is I believe where we are now with avast 5.0. For those on older OSes Alwil have said they would be supported to the end of the year and that is in the form of the avast 4.8 version still being available for those OSes. So at the end of that period who knows if that will continue.
Alwil has been very good in providing a free version for those who can't really afford the Pro version, but that generosity has to be tempered with how much it costs to continue supporting older OSes that even MS abandoned years ago.
Moving to version 5.0 yet still maintaining compatibility with win9x, winME for what they have planned isn't possible without holding back the newer OSes, effectively that could lose avast the higher protection that will come with that upgrade. So for a period of time they will have to devote time and money maintaining 4.8 and its VPS update system and updates in support a dying OS with less and less users; at some point that will have to end and that is unfortunately a commercial reality.
So understand this, at some point in time there will be zero AV support for win98, winME, then will your OS do what you want of it and I presume being able to use your system and be protected from malware.
I'm not telling you to upgrade your OS, simply telling you how it is, avast 5 won't support win98 or winME as has been stated on numerous occasions already. At this point in time with July as the likely release date for avast 5 there is no way they could re-engineer it to be compatible with win98 and retain what improvements that are planned.