New Computer Causing Internet To Die On Entire Network

After recently setting up a new computer, my entire network seems to randomly loose internet connection. The interval between connection losses is as short as half an hour but it sometimes goes several hours without dying; the connections is lost for anywhere between 30 seconds and 20 minutes each time it dies.The new computer is running Windows 7 and is using a Roeswill USB wireless adapter, but I have tired it with a wire and the connection still dies. I am disinclined to believe that this is caused by a virus simply because this is a brand new computer that has had only minimal use; to be on the safe side, though, I did do virus scans with multiple programs, however, I did not find anything.When the connection is lost, a yellow exclamation appears on the task bar's internet access icon. If I check my available networks, my network still shows full strength. I have tried disconnecting and reconnecting but nothing happens; I don't get any "failure to connect" type errors nor do I get connection back. I have also tried physically removing the adapter/wire and plugging it back in, but that doesn't do anything either.

I am under the impression that the new Windows 7 computer is doing something to temporarily kill the entire network, but I don't know what.For the record, my modem is an old Motorola and my router is an old Netgear. Both are quite a few years old, but I don't think they are the problem as my internet was fine before I added the new Windows 7 computer. There are wired computers and wireless computers running XP, Vista, and 7 also on the network.