I run fully up dated XP, with an external Hard Drive a Philips SPD5100cc/05 with no trouble until last weekend. On Saturday I backed up my computer hard drive OK
Sunday I tried to get into the back up,

1) Windows would not boot with the Philips drive switch on
2) It did not show in My Computer
3) On checking F: Properties it read Type Local, File System RAW, Used Space 0,
Free Space 0, Capacity 0
4) It would not re-format, I tried it on my laptop, it would not work, but it would boot with the hard drive switched on. I was told the drive was US.
5) I bought a replacement Maxtor PN 9NZ2A4-500 tested it out on my laptop works OK
6) Set it up on my desktop, on the same USB and it will not run or show in My Computer
7) If I use a USB on the front of the Computer the hard drive works WHY
8) Did the Philips hard drive change something when it went belly up
9) If so what, and can I change it back
10) To check it the USB still works, I put a memory stick in the USB that the Philips was in and it works, so why will the memory stick work and not the hard drive.

Any Ideas

I have found the answer Faulty USB port.

Right-click My computer > Properties.

Click the Hardware tab > Device Manager.

Scroll down to Universal Serial Bus controllers and click on the + to the left.

Right-click on each one in turn and select Uninstall.

Confirm to delete.

Once done, restart the computer and let it reinstall all the USB connections.

Now try again.

If the flashdrive worked and the drive didn't, how can the port be malfunctioning. If you uninstalled all the ports and re-booted did you check all ports were functioning?
JC

Only the USB did not work that the Philips ex-hard drive was in when it went belly up.

All other USBs worked OK with the Maxtor PN 9NZ2A4-500

Now they are working fine