My description is based on Windows 95/98, because I'm sitting behind one at the moment. But it won't be very difficult to translate it to XP. If you don't succeed with that, please let it know and I'll move to an XP-computer tomorrow morning (that's tonight USA time).
Ping uses a DNS-server on the Internet to translate an url (like www.metallica.com) to an ip-address (like a browser does in the background). If anything goes wrong with that, you get a DNS-error.
The setting of the DNS-server to be used is in the TCP-IP-properties of the dial-up connection (My Computer>Dialup Connections, select it, right click, properties) go to second tab (servertypes) and click on TCP-IP settings. Carefully note the settings so you can go back to them.
It's possible that they point to a bad server somewhere on the net (could even belong to your ISP, although they should have let know it). Or it's possible some software on your PC is corrupted.
The first thing to do is to find out if it's your problem or their problem. Find the dialup settings recommended by your ISP (they should be on their site, or the helpdesk can tell you what they are). Then make a new dialup connection according to those instructions (like you did the first time, but with another name, if possible) and see if ping behaves now. If not, repeat the exact operation on a computer of a friend or relation. It should have a dial-up modem, and that's all it needs. If it works there with the same settings, obviously it's a problem located on your PC. If it doesn't work there either, it seems to be you ISP's problem. Making a new dialup connection and changing its properties is totally harmless, and you can delete it afterwards.
Those DNS-servers are either assigned by the server (ISP) as you connect or (more likely with dialup) fixed. My provider (wanadoo.nl) now recommends using: Primary DNS-server: 220.127.116.11 and
Secundary DNS-server: 18.104.22.168 (see last two lines at the bottom of http://www.wanadoo.nl/mijnabonnement/verbinding/verbindinginstellingen.html - sorry it's Dutch, but you'll understand those 2 lines). You can use those settings for the DNS-servers and see what happens. If it works with those, it's clearly a problem located with your ISP. Or find any other local ISP help page and see what DNS-servers they use. It's all on the Internet, it all works, and it's all free.
And let me mention that you can use winipcfg (or the XP-equivalent, I think it's ipconfig) to see the dns-server used by your connection. That should match with the settings.
- remake your dialup connection
- check the DNS-server used with winipcfg/ipconfig
- try your ISP's settings at a friends computer
- try another DNS-server at both your own and your friends computer
Frankly, I don't believe in spyware randomly and transiently blocking certain ISP's, nor do I believe that reinstalling java and scripting will help. But a good spyware and virus check (spybot, panda online and housecall online) certainly won't harm.
The same goes for 2 nice repair utilities LSPFIX and WINSOCK2FIX, that you can search with google to download. They correct situations where Internet doens't work at all, and yours is rather different.
And I wonder what your ISP has told you to do and try during those sessions on the phone. Checking and changing the DNS-settings should be routine for them under these circumstances.
Sorry if it's technical. It is technical, that's the problem.