Riddle Me This...

So I wanted to perform a 'covert' upgrade of an old Hub on our network at work, hopefully to allow full 100Mbit 'Fast Ethernet' to reign. As far as I know, the hub is the only device on the network that isn't 10/100 Ethernet, it's just 10Mbit. However, as soon as I swapped it out for this 8-port switch, one machine refused to admit that it was in fact plugged in. I tried multiple ports on the switch and every other machine that was plugged into the new switch behaved fine.

Another odd behavior noted on this network that I wanted to address by upgrading the switch was some (but I don't think all) computers on the network lose some or all network connectivity if a network cable is left plugged into a switch without also being plugged into a computer.

The infrastructure is as follows:

Cable Modem
         |
Linksys Router w/Switch
 |||              |
Empty    8-Port Linksys 'Workgroup' Switch
        ||||||            |             |
        Computers      'Server'     Old Hub
                                     |||||
                                   Computers

The 'Server' doesn't do any routing or anything, it does run Server 2003 and hosts an Exchange server for mail, as well as serving as general storage for files and our database(s).

Eventually I want to just get a 16-24 port switch and run all the network cables back to the 'server closet' (my old office I used to share with the server) and not bother with this 'daisy chaining' or 'cascading' as the hub seems to call it.