Power cycle your router, cable modem and then shutdown and restart your pc if you havent.
if it still doesnt work
goto windows button in the corner type CMD in the search box and hit enter.
then type tracert
www.addressthatdontloadhere.com
also what security programs do you run?
firewall/antivirus/antimalware/ip filter/etc
you should get something like this
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
C:\Users\Rand>tracert
www.google.com
Tracing route to
www.l.google.com [74.125.225.16]
over a maximum of 30 hops:
1 16 ms 20 ms 19 ms FUNNYMONKEY [192.168.1.1]
2 36 ms 58 ms 70 ms cpe-76-189-32-1.neo.res.rr.com [76.189.32.1]
3 58 ms 32 ms 37 ms gig1-1.akrnoh6 swt401.neo.rr.com [24.164.119.1]
4 45 ms 27 ms 42 ms tge1-50.grenoh1-swt402.neo.rr.com [24.164.119.13
2]
5 38 ms 14 ms 26 ms tge1-8.grenoh1-swt401.neo.rr.com [24.164.110.70]
6 25 ms 39 ms 29 ms tge1-4.ncntoh1-swt401.neo.rr.com [24.164.110.64]
7 36 ms 29 ms 40 ms tge5-0-0.ncntoh1-rtr1.neo.rr.com [24.164.102.170
]
8 34 ms 39 ms 49 ms tge4-0-1.ar01.clmkohpe.mwrtn.rr.com [65.25.137.1
3]
9 39 ms 87 ms 39 ms ae1.tr00.clmkohpe.mwrtn.rr.com [65.189.140.128]
10 62 ms 49 ms 51 ms ae-4-0.cr0.chi30.tbone.rr.com [66.109.6.68]
11 50 ms 59 ms 60 ms ae-1-0.pr0.chi10.tbone.rr.com [66.109.6.155]
12 39 ms 49 ms 51 ms 74.125.48.109
13 57 ms 62 ms 67 ms 72.14.236.176