The Dell Inspiron 5100 was one of the best-selling Dell models of the early 2000s. A durable laptop model, the 5100 is still in use by a number of original or second-hand owners. Typically after a few years of use, a computer system can get a bit slow due to an excess or start-up programs, a fragmented or too-full hard drive, plus possible malware infections. One way to fix these issues is to simply start over by resetting the computer to factory settings.
Power up the PC. Or, if the PC is already turned on, shut it down and then power up the system.
Some Dell systems come with DSR (Dell System Restore) on a hidden hard disk partition. To use DSR, restart your computer. When the Dell Screen flashes, press and hold
If you find that your Dell does not have DSR, look for a restore or system CD that should have come with your computer. Insert this CD into your drive and restart the computer. Press a button to boot from CD.
Follow the on-screen instructions to format your hard drive, reinstall Windows and reset your computer to factory specifications.
This procedure will delete or write over all content on your hard drive. Make sure and backup any data you do not want to lose before attempting to restore to factory settings.