were you trying to get to safe mode in Windows using F8 ?
what version of Windows ?
what laptop model ?
for most modern Dell's F12 before Windows loads (bios startup messages enabled ?) may get you into the 'select boot device menu'
(including:- hard disk, optical drive, usb device, pxe network, recovery partition)
You should got to www.dell.com and download the user guide for the exact model Dell laptop you have
If you go to recovery partition & run system recovery you will probably format hard disk & lose all data so backup anything important first.
You should go to the Dell support page and enter in you express service code to get your computer sepc's brought up and then get instructions on how to access the recovery partition and how to use it. It's one thing to access the partition but to know how to use it so you on't lose your data is another. I had a Toshiba laptop that was having big issues with the OS and on thier suport site I got instructions on how to access the hidden recovery partition and what to do with it and te problem was resolved very quickly.