The reason for no F8 menu is because you overwrote the WinRe file in Windows 7 which provides the System Recovery Options
which is where the Dell Recovery hotkey was rooted.
Without the Dell Recovery disks your options now are to Clean Reinstall Windows 7 Factory OEM
or to order the Recovery Disks from Dell. However on many models they only provide a Windows 7 REinstallation DVD so you might as well use the DVD in the blue link and get the same clean reinstall now - if you didn't make Recovery Disks.
Once you reinstall Windows 7 you might be able to recreate the link to Dell Recovery Partition - restoring F8 link
. So for that reason you might want to save Recovery Partition as well as the Dell Tools partition if it will run from its hotkey which is normally separate from F8.