Windows 7: Windows 7 not recognizing external hard drive

I have windows 7 64 bit and I'm trying to copy data from my old desktop which won't boot up anymore to my laptop. It is a 3.5 inch sata hard drive which I connected to a usb external hard drive dock. But when I plug it in windows just doesn't recognize it and it doesn't appear in windows explorer. When I go into disk management it recognizes it but says it is not initialized and asks me if I want to initialize it. I'm reluctant to do this as I'm not sure if it will wipe the drive. Any ideas on how I can view my files?
It is a 300GB drive split into 3 NTFS partitions which has both windows xp and windows 7 installed on it. (I'm not sure if that makes any difference.)

I think it can be initialized without losing anything. Windows apparently can't read the drive's signature and if you initialize it it'll write a new signature to the boot record.

The first thing I think I would do if I needed data on the drive is use a bootable Linux CD/DVD to see if it can read/copy the files off of it:

Put Lucid Puppy on USB Flash Drive from Windows | USB Pen Drive Linux