You may have a Dell Dimension 9150 if it is a desktop.
Dell models would show it as a 9100 series unless you enter your service tag on the main support page.
Inspirons are laptops. I have an 8900 and a 9100 inspiron laptop.
Dell using similar model numbers for laptops and desktops will continue to cause confusion for years.
The dimension 9100 has a sata drive.
A Dell Inspiron laptop
9100 has a 2.5" ide drive. There is usually a blade to pin adapter on the drive. Standard 2.5 ide to 3.5 ide adapters will allow you to mount the drive in any desktop. It is set to single master by default so you might need the adapter which includes a master slave switch or look up the jumper for the drive.
An external sata enclosure with a usb connection to the computer is available on amazon for between 7.00 and 40.00. I use the cheap ones so I can give them away to clients after I recover their data. External ide enclosures are also available but you will need he 2.5 size specifically. Sata drives of any size work in the external sata enclosures but the 2.5 might rattle around in a 3.5 size case.
SATA pci cards are also cheap.
Do you have the recovery dvd/ or cds you made when the system was new? (Some models gave you the option of pre printed recovery disk sets at time of purchase.)
If you cannot find the details post the service tag
Does it look like the one on this page?http://support.dell.com/support/topics/glo...&~ck=anavml
or like this one:http://support.dell.com/support/topics/glo...&~ck=anavml