Check the boot order in the Bios to make sure that it is correct. Hard disk drive, CD/DVD drive and Floppy if used. The hard drive, IMHO, should always be first boot device.
If available, set the PXE (Network Boot) to disabled.
Check cable connections (reseat),
Check jumpers on hard drive for Master/Slave or Cable Select settings. CS should be avoided unless using a CS cable.
Do not have both HD & CD/DVD on the same IDE cable.
When booting, continually tap the F8 key, this should invoke the Boot Menu so as to boot to CD/DVD.
And lastly, have your BIOS rescan your HD, or, reset your BIOS to defaults.
I take it as read that you are using IDE drives throughout.
have fun! good luck!
Looks like a hardware problem, specifically the disk. Most laptops' hard drives just push into a slot so take the disk out, clean disk connector and laptop connector with a brush then refit & make sure it's pushed home securely.
As you've had an OS previously installed the hard disk jumper is probably in the correct position but as Mucks says, worth checking.
Other than that, you may need to completely wipe the hard disk. This can be done by downloading some free disk software (try the Seagate site) burning it to a CD, booting from that CD then writing 0's to the whole disk with the software, thus erasing it.
Then when you boot from the Win 7 disk it should give you the instruction to format the disk prior to installation.
Good luck.