Take a look in the BIOS to see if the drives show there. The key to enter the BIOS is shown on the startup screen. If neither the floppy or hard drive show up in the BIOS, probably had a hardware failure.
You can start the investigation by looking here and entering the proper info:
Dell Optiplex 170L Series
Intel Celeron Processor 2.40 GHZ
Level 2 Cache: 256 KB Intergrated
Turn on my sons computer today and after the dell logo screen comes up, i hear 2 beeps.The following message comes out.Strike F1 to retry boot, F2 for setup utility. (Picture of what I see) ---> http://i34.tinypic.com/10d8pi0.jpg
I also tried to install windows on it again and this message comes up.(Look at the PIC) http://i36.tinypic.com/10qcc9y.jpg
Any help I would really appreciate it. Thank you.