I know you do not have any data to save but if there are programs that you have that need a key or serial number to be installed you need to collect those before performing the factory reset.
And if you decide you do have some data you want to save please let me know before going on to Step 2.
Sony Factory Reset
The directions for this are here
Please read carefully and come back to me with any questions you might have.
The key is entering the recovery partition with tapping b] F10 [/b] when booting up and then once you see boot.ini, hitting Enter when you get there that opens VAIO Care Rescue.
Once you complete the reset please give me an update.