IBM t42 BIOS does not recognize hard drive

i took the old hard drive out and put in a seagate 160GB one and now BIOS does not recognize it. it won't even recognize the old hard drive when i put it in. i put the hard drive into an external USB thingy and both of them work.

when it tries to boot it will say OS not found and something about please check cable

any suggestions?

you may want to look here: http://forum.thinkpads.com/ they know a lot about thinkpads.