Wondered about connection problems?

Wondered if anyone else might have had strange connection problems the past few months. I have the modem shows it is connected but most sites you visit cannot connect. When this occurs IE, MSN, even visiting here cannot connect, but at the same clicking on Yahoo messenger and another program connected with no error message. Why at least two times I had no problem connecting with Yahoo messenger but did have problems with almost all the other major sites?

At the time I wondered if DNS servers could possibly have a cause and effect relationship. Not sure why one or two sites will load but not most others?

As I said I have noticed this 2 or 3 times since the begiinning of the year.

Not sure if this some how if this could be involved either by the malware experimenting or the DNS server owners in the connection path attempting to resolve a network problem that shows up.

Oh for about 2 years I have been using OpenDNS.

UncleDoug