CPAX20/other weird errors and unstable internet connection

Hi,

I have Windows Vista HP 64-bit.

I've been getting these weird errors that say things like 'Runtime error big-long-number.' I haven't installed any programs recently and the weird format of the error messages (many of them said something about CPAX20 and Google only shows a little bit about how this is related to alg.exe) made me think it was spyware, but I ran Spybot and it's clean. I've also done a virus scan (AVG) which found nothing.

Another one popped up while I was writing this, it's the smaller error I've attached... The internet on this machine worked fine until about 2 hours ago. It works for about 30 seconds after rebooting the machine, then it stops. My wireless connector will say "Connected to local only." I have other computers wireless connected just fine, one of which I'm posting this from.

I have googled 800c0005 and it appears to be something about MS XML and only related to Windows Server 2003. Any ideas? The fulle error from the big dialog box is attached, as is my HJT log.

Note, concerning CPAX20 and the alg.exe, this line from the HJT log seems odd:

O23 - Service: @%SystemRoot%\system32\Alg.exe,-112 (ALG) - Unknown owner - C:\Windows\System32\alg.exe (file missing)

Edit: I forgot to mention I have also run CCleaner and SUPERAntiSpyware. I have reset winsock as well.