The mouse “locking-up” may or may not indicate an interrupt conflict with a network adapter, which could slow-down the network. Or the lack of mouse responsiveness could occur because the system is busy. What kind of mouse is it: PS/2 or serial? Larry
Q. Why would 100BASE-TX network adapters only operate at 10 MHz when two computers are connected with a long cable?
A. This can be caused by a defective cable, the wrong kind of cable, a cable that is improperly installed, the wrong kind of RJ-45 plugs, cables that are not wired properly, a bad crimp, or defective network adapters. It can also happen with poorly made or improper cables of any length.
The cable should be solid core and rated CAT 5 or higher (jacks and short lengths of stranded cable can be used at either of both ends of the cable--see reference at the bottom of this page).
The cable should be installed following the rules at http://duxcw.com/digest/Howto/network/cable/cable9.htm.
The RJ-45 plugs should be rated CAT-5 or higher and designed for solid core wire (there are RJ-45 plugs for stranded wire).
The cables should be wired according to http://duxcw.com/digest/Howto/network/cable/cable6.htm. The important thing is that the Ethernet transmitters be connected to the Receivers with wires for the SAME twisted pair. If they are not you may see the symptoms you describe, especially with longer cables.
Bad crimp: see All About Crimping at http://duxcw.com/digest/Howto/network/cable/cable8.htm.
Run diagnostics and C:\>net /diag on the adapters.
What are the maximum and minimum cable lengths allowed for a 100BASE-TX unshielded, twisted-pair (UTP) Ethernet? at http://duxcw.com/faq/network/cablng.htm.
Does the order of the colors of the wires in a straight-thru twisted-pair network cable matter as long as both ends are the cable are wired the same? at http://duxcw.com/faq/network/ends.htm.
Why would the Link (or LNK) LEDs be on solid, if there is a faulty cable connecting two Ethernet devices? at http://duxcw.com/faq/network/link.htm.