To check your ISP, run dig to see if your DNS can resolve the domain name. Open a terminal and do:
When I run it, I get the following. Note the bits in read being important confirmation that my DNS can resolve the domain name.
vincent@nadia ~ $ dig megatokyo.com
; <<>> DiG 9.8.1-P1 <<>> megatokyo.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 59190
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 0
;; QUESTION SECTION:
;megatokyo.com. IN A
;; ANSWER SECTION:
megatokyo.com. 3318 IN A 67.210.248.26
;; AUTHORITY SECTION:
megatokyo.com. 3318 IN NS ns1.megatokyo.com.
megatokyo.com. 3318 IN NS ns2.cologuys.com.
;; Query time: 26 msec
;; SERVER: 127.0.1.1#53(127.0.1.1)
;; WHEN: Sun Dec 9 15:04:03 2012
;; MSG SIZE rcvd: 92
Try to visit
http://67.210.248.26/, which is from above the IP address of megatokyo.com. If you can not resolve the domain name on your ISP, but you can access the website at its IP address, then you could consider switching to a DNS other than your ISP's DNS.
If you can also not reach this website at its IP address, the admins of that website may have banned your IP address (for spamming or other misconduct), or your ISP may have a block on this website and IP address for some reason.