How abou trying to simple diagnostics first, before you moan? I for one am sick to death of people such as yourself, not doing anything to "help". Othr than moan liek a spoilt child. Do the things below.
At the times you are having issues, do the following
start >> run >> CMD >> ping
www.virginmedia.com
Post the results
2nd >> Whilst in cmd >> tracert
www.virginmedia.com
Post the results
3rd Visit, in your bowser,
http://192.168.100.1. Go to Signal then post both up and down stream.
4th Speed test >
www.speedtest.net post the results.
5th:
http://gamefiles.virginmedia.com/blueyondergames/ chose two files, download them together, post the results.
6th, are you running any kind of router or are you direct to modem via ethernet.
Run all the above results, with both direct and none direct.
Clearly, these steps will be amost the same as TS ask you. This should give you some amunition to fire at them, when they try and blame it on Syware programs.