P-L:
The way you install Laplink is by connecting the serial ports together with a Laplink cable. This cable has two plugs at each end, i.e. a 9 pin and a 25 pin at both ends.
You load up the software and have it running on the 'good' PC then turn on the other PC and you type in a command at the DOS prompt. This tells the remote PC to load the linking software through it's COM port.
Once you have installed the Laplink software over the COM port it is best to change over to a Parallel link cable between the two PC's as transferring the CAB files for 98 etc takes a long time over the serial port.
You may find that the transfer over the Parallel port will be no good. Laptops are normally configured differently and some use the LPT for other stuff.
Good Luck!
------------------
400 Hertz but DC is easy