external hdd not recognized?

i put the internal hardrive of my old pc( having problems booting up, but i was told it wasn't an hdd problem) to an external hdd enclosure so i could retrieve files/folders from the old drive. The thing is, when I plugged into my laptop, it doesn't show up in my computer or disk management, only on device manager.My laptop recognizes its there, but i cannot access the files. The old hard drive is a 3.5 ide 80gb. somebody told me that i needed to install drivers in my laptop for the old hard drive to work, but would that mess up my laptop configuration? I am new to this, and I only have one working computer as of now. How do i access these files? thank you. the laptop i am working on is a compaq nx 6310, while the old hard drive is from a presario 6420nx . both run windows xp ( professional and home edition respectively)

 

It sounds like you may need to set the jumper on the HD in the external enclosure to either CS for Cable Select or set it to Master. It depends on the external enclosure that your using.