The error described here http://support.microsoft.com/kb/330174/en-us starts to appear :
Strange? What did I change in my computer?
The solutions there did not solve the problem…
Only avast file is having this problem…
There is 20,4 Gb free on that partition…
Strange… I have really no idea what might cause this, but I don’t think it’s in the powers of avast! (i.e. the trouble must be somewhere in the OS).
How often does it appear? If you are running a scan, for example, does it occur once or multiple times?
Well if you can backup data now, do it. Coz you might not be able to do this tommorow…
Then check your HDD health with program called HDDLife (freeware).
This error accours when HDD fails to write data to disk after being cached to its internal HDD cache. This is a quiet common symptom of dying HDD.
It can also be a problem with IDE drivers but if it was working ok till now and you haven’t been messing with IDE drivers, then HDD will most probably die soon. Mine ended like this too. First it started showing me this error, few days later it started scratching badly from time to time, few days later it started failing when i tried to format it and in the end PC stopped booting and showed error that no boot device is present.
Yeah… I feel the same.
No… It’s not frequent and since booting it disappered.
I wasn’t running a scan at that time.
Regular backups done.
My HDD is ok. Its SMART status is ok.
Yeah… but this time seems some ‘low level’ driver or whatever… not a hardware trouble.
I’ll pray for this does not happen with me 
:-\