I have a friend with an older pc that has xp on it. The pc will turn on and just turn off shortly after. She wants to just turn the hard drive into an external drive. If we turned the drive into an external drive could that work with a mac? The mac operating system is mac osx version 10.4.10. There arent any applications she would need off of it just music and text files for the most part. I know nothing of macs so any help would be appreciated.

Yes and No.

You can take that drive, put it in an external enclosure and connect it to that Mac and you WILL be able to read/copy the files off of it.

The problem is that you won't be able to write files to it if the drive is formatted as NTFS (which is probably is unless its a REALLY old computer, like 7+ years). If the Mac has enough hard drive space she could put the files on the Mac's hd temporarly, then open up the Disk Utility in OS X (Applications -> Utilities -> Disk Utility) and format it as FAT32. Then copy the files back. If the drive is FAT32 both Windows and OS X will read it and write to it (as well as just about any other OS).

Thank you for your answer that is exactly what I was looking for.