CP Trader: Q1) Many vendors put a hidden partition on your drive and that becomes the system backup. They do not provide a backup DVD for your operating system. In the event of corruption in the working area of your C drive (the operating system portions,drivers, and possibly other programs) the vendor has a utility that allows you to copy from the hidden partition and overwrite the bad stuff. Of course you must then download a very large number of patches to get back to where you were. Windows also creates a number of hidden areas such as the "Restore" files. They can take up a lot of room depending on how you told Windows to use the Restore feature (or the default if you did not get involved). Q2) With just one hard disk the only advantage, in my opinion, is the ease in backing up data files without using a backup program. By storing all data in the D partition you can copy the entire partition easily without using a backup utility. However, the Windows backup utility in Win 7 is pretty good and lets you select what you wish. Type "Backup" in the start box and then get help inside the backup program to see if it will serve your needs. Jack
OS drives are notorious for failure due to corrupt files, virus, etc. Having the partition at least may limit the damage to the OS. Having your data on that other partition can be a benefit. But another physical drive is preferred.