The reason Mechanix2go asked that is if the drive is larger than 137gb manufacturer's size ( = 128gb in Windows) Windows on the other hard drive must have at least SP1 updates installed in order to see the full size of the second drive. However, even if it didn't have SP1 or SP2 updates it should still see the drive, but only as a maximum 128gb in Windows.
"Do not understand suggestion to take ownership of files/folders in second HD. Where would they show?"
As far as I know, that only applies if you CAN see the drive in My Computer or Windows Explorer, but when you click on at least some, or all, of files and folders, Windows will not let you access them.
"Reformatted as computer was slow."
Zillions of things can cause that. You usually do NOT need to re-format the partition Windows is on. There are lots of other things you can try, and check for.
Sometimes all that is wrong is your C partition is too full.
It takes less than an hour to run Setup, but it may take many days to get your Windows installation and all the programs you had installed before to the way they were before.
It is common to un-intentionally damage IDE data cables, especially while removing them - the 80 wire ones are more likely to be damaged. What usually happens is the cable is ripped at either edge and the wires there are either damaged or severed, often right at a connector or under it's cable clamp there, where it's hard to see - if a wire is severed but it's ends are touching, the connection is intermittant, rather than being reliable.
Another common thing is for the data cable to be separated from the connector contacts a bit after you have removed a cable - there should be no gap between the data cable and the connector - if there is press the cable against the connector to eliminate the gap.
80 wire data cables are also easily damaged at either edge if the cable is sharply creased at a fold in the cable.
Try another data cable if in doubt.
If that doesn't help....
Check your hard drive with the manufacturer's diagnostics.
See the latter part of response 1 in this:
(thanks to Dan Penny for this link:)
Hard Drive Diagnostics Tools and Utilities
If you don't have a floppy drive, you can get a CD image diagnostic utility from most hard drive manufacturer's web sites, but obviously you would need to make a burned CD, preferably a CD-R for best compatibilty, on another computer if you need to.
If the hard drive itself passes the diagnostics, your problem can probably be fixed one way or another.