I have a XPS/Dimension 400/9150 and have had trouble with two drives when using internal drives externally via usb. System starts to not recognize drive and eventually doesn't recognize ntfs formattng. I have a second internal drive and have never had this problem.
The motherboard has four internal SATA connectors and I'm already using one for a second internal drive.
Question is:Can I use another one of those SATA connectors for a third "internal" drive. If that is OK the stupid question is what do you power the drive with since there are no more connectors on my internal power cable.
I'm a photographer with back-up problems. Want a system drive and two swappable drives for redundant storage without this problem of faulty usb connections or whatever it is.
I may be wrong but let me put it out there... USB drives draw a lot of power... and we all know that dell does not have the best PSU's. they also make pci cards to add USB ports. I would be rethinking your drive solutions.
Are you sure there are nothing wrong with the drives? I'd be worried that the PC works fine but the drives (or USB enclosers) are failing.
If everything checks out then yes you can put it inside assuming you have a spot to mount the drive. If you don't have anymore SATA power plugs you can get a "molex" to SATA adapter.
Edit: Forgot to mention that Dell actually has some of the best OEM PSUs. Their 305 and 350W PSUs were near legendary. I wouldn't worry about adding one more hdd to it. (more so if your external drive was plugged in via USB and didn't have its own power brick.)
The external usb enclosures both have their own power.( Have had same problem with two different enclosures, different makes). Second drive just started failing but when connected internally via SATA problem disappeared. I have been reading on net that people have this problem with external enclosures and I just don't want to mess with it.
This molex to SATA seems to be what was missing. The dell PSU cable still has a four pin connector empty.
So I'll plug another drive into second motherboard SATA port and power it with a molex to SATA cable. That gives me a system drive and two internals that I can swap as they fill up. I'll only use USB for occasional use.
I'll just set the third drive on top of the cabinet, securely, there are no more bays.
That solves my problem if this scenario seems plausible.