"Realtek PCIe FE Family Controller Series v1.24 (10/07/10) PXE-E61" is your network card which the machine is trying to boot off of since it isn't detecting the hard drive. I would try removing/reseating the hard drive to make sure its seated properly. If you do that, and it's still not booting you could try replacing the drive/reinstalling OS if the drive shows up. If the new drive isn't detected then the laptop is likely not worth repairing, although you could contact Dell or take it to a repair center for another opinion.
Unfortunately you have to remove the bottom casing on the machine to check the hard drive connection which is not something I would recommend unless you are comfortable working with delicate electronics.http://support.dell.com/support/edocs/systems/insm5040/en/sm/hd-assem.htm
Best bet is to take it somewhere to be serviced if you are not comfortable taking the laptop apart.