I still use IE5, and have found no real difficulty getting support from Microsoft. You do have to go get it, though.
Because of an old business email account with MSN, that uses POP3 protocol, we are locked in to IE5 - since MSN tells us that we would have to change the email address, due to POP3 not being compatible with later versions of IE. Most notoriously - with IE5.5.
Anyone using IE5 should have downloaded the "SP2" upgrade long ago.
Anyone doing any "secure" transactions, and needing "high" encryption, should have upgrades Q295106 and Q306121.
You should be able to find the download sites fairly easily by looking for a connection to the "Knowledge Base" from microsoft.com. I'll try to look up more specific directions later, and post them if there is a need; but I would really recommend "wasting" a bit of time looking at what support is there.
I haven't looked at the particular virus that originated this thread, but my impression is that the above "fixes" would have prevented it from getting in. - Maybe more on that later.