Many network problems that affect your access to the Internet, such as the currently obnoxious "Server Error 1-500", can be better understood, if we can understand how you are connecting to the servers in question. A tracert log is very useful in this case.
tracert www.google.com >c:\tracert.txtat the command prompt.
tracert www.yahoo.com >c:\tracert.txtIf you may be having a DNS problem, find out the IP address of the server, and target it, for comparison.
tracert 66.249.89.99 >c:\tracert.txtHere's a sample log.
C:\>tracert www.google.com
Tracing route to www.l.google.com [66.249.89.99]
over a maximum of 30 hops:
1 1 ms 1 ms 1 ms 192.168.1.1
2 40 ms 43 ms 41 ms 10.122.84.253
3 42 ms 41 ms 43 ms 10.122.84.254
4 54 ms 55 ms 55 ms 10.121.20.1
5 * * * Request timed out.
6 51 ms 53 ms 51 ms 58.147.0.52
7 53 ms 51 ms 53 ms 58.147.0.46
8 268 ms 275 ms 271 ms 202.47.254.161
9 270 ms 269 ms 269 ms 202.47.253.148
10 280 ms 283 ms 283 ms 203.208.191.197
11 297 ms 299 ms 283 ms ge-0-1-0-0.sngtp-cr1.ix.singtel.com [203.208.149.201]
12 283 ms 339 ms 285 ms so-2-1-0-0.hkgcw-cr2.ix.singtel.com [203.208.154.38]
13 114 ms 115 ms 113 ms 72.14.196.5
14 118 ms 117 ms 117 ms 216.239.43.68
15 144 ms 137 ms 141 ms 66.249.95.198
16 142 ms 137 ms 139 ms 72.14.232.166
17 178 ms 171 ms 167 ms 72.14.236.236
18 175 ms 173 ms 175 ms 66.249.95.197
19 176 ms 181 ms 177 ms 216.239.47.54
20 176 ms 177 ms 175 ms jp-in-f99.google.com [66.249.89.99]
Trace complete.