Semi-access to the Web under w2k-sp4

I've been running W2k-SP4 for a few years with no problems on a 2.8 Ghz Pentium 4 pc. Suddenly, I can no longer access the Web through Firefox (call to Google hangs) nor my router. On the other hand, I ping www.google.com and the router successfully. Furthermore, Avast updates itself normally.

Last, but not least, if I go into the Connection Wizard, the "Connection to Internet" option is grayed out, while all other options are available.

I ran an SFC /scannow to no avail. I'm really stuck because I have important programs on it.

I restored a week-old copy which I had saved on an external disk. No change.

I am reporting this bug through one of my laptops going through the above-mentioned router in an ADSL environment.

 

Problem solved. I stopped the Web Shield in Avast and everything works fine now. This problem does not appear in XP. Must come from the last Avast update I had.