If You Can't Update--- And A Bit More---

Hi,
I mention below a series of performance and access problems. I am wondering if they somehow might be inter-related:
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For the past few weeks it appears that Anti-Personal Edition related websites and updates have been almost impossible to access. If one does manage to get a download or update (and it is a very slow download), frequently the downloaded files are damaged.
For a short period of time I had thought that this might be related to some type of strange web exploit, as another anti-virus software program on my computer began to experience simular problems.
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I had recently been invited to participate in a commercial and legal music download website in Argentina which utilized Windows Media files.
I later have noticed what appeared to be some hesitations from time to time in my computer operations.
I am thinking that these might be related to something added by Windows Media and have come up with some references to the cdr4 and related files utilized in Windows Media player burning software.
I removed that part of Windows Media and any cdr4 related files.
Now I am seeing that Roxio has an update related to the cdr4 files, and that they have been mentioned in regards to interference with the use of some anti-virus softwares.
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This may be a third topic...
I am wondering if the users of other anti-virus software experience this sort of drop-out in service, availability of updates, etc.
When does one decide that a software provider is no longer able to support their software adequately anymore? Is this simply the law of the land in cyber-space, drop-outs in service and such? It seems somehow scandalous to me to not be able to update an anti-virus software. What good is it anyway in that manner? If you have a car without gas, at least you can sleep in it for lack of other uses.