when it does happen again, could you do "start" -> "run" then type "cmd" to get a dos box.
once there, type "tracert www.audi-sport.net" (without the quotes) and copy and paste the results here ?
You should get something like this :
C:\Documents and Settings\Administrator>tracert
www.audi-sport.net
Tracing route to
www.audi-sport.net [207.218.208.17]
over a maximum of 30 hops:
1 1 ms <1 ms <1 ms 192.168.0.1
2 35 ms 13 ms 26 ms cr0.smhh.uk.easynet.net [82.108.10.176]
3 8 ms 7 ms 7 ms ge3-0-0-2007.ar3.enmik.uk.easynet.net [82.111.103.209]
4 10 ms 7 ms 7 ms ge1-3-0-41.br1.enmik.uk.easynet.net [82.110.126.17]
5 8 ms 21 ms 8 ms ge0-0-0-47.br0.enmik.uk.easynet.net [82.108.6.137]
6 9 ms 9 ms 9 ms so0-2-0-0.br0.enhmi.uk.easynet.net [195.172.211.149]
7 9 ms 10 ms 9 ms 82.108.6.142
8 9 ms 9 ms 9 ms so1-1-0-0.br1.thlon.uk.easynet.net [195.172.211.145]
9 10 ms 10 ms 9 ms ge0-1-3-0.er3.thlon.uk.easynet.net [217.204.60.94]
10 29 ms 10 ms 10 ms ge3-0.pr1.lhr1.uk.above.net [195.66.224.76]
11 81 ms 83 ms 82 ms so-7-0-0.cr1.dca2.us.above.net [64.125.31.186]
12 95 ms 93 ms 93 ms so-4-0-0.mpr2.atl6.us.above.net [64.125.28.230]
13 92 ms 92 ms 93 ms so-0-0-0.mpr1.atl6.us.above.net [64.125.27.49]
14 106 ms 105 ms 105 ms so-4-0-0.mpr2.iah1.us.above.net [64.125.29.70]
15 121 ms 120 ms 120 ms 289.ge-3-2-1.mpr1.iah1.us.above.net [216.200.251.26]
16 120 ms 121 ms 129 ms ivhou-207-218-245-29.ev1.net [207.218.245.29]
17 122 ms 121 ms 122 ms ivhou-207-218-223-118.ev1.net [207.218.223.118]
18 121 ms 121 ms 120 ms ns1.siteground128.com [207.218.208.17]
Trace complete.
C:\Documents and Settings\Administrator>