|"What do you mean by the jumper and where do i find the battery?"|
The jumper is the Clear Cmos jumper or similar on the mboard. Where it is is shown in the manual for the mboard - there is often labeliing on the mboard beside the jumper but that can be confusing. You remove the AC power to the case, move the jumper to the Clear position, wait a few minutes, move it back to the "normal" position, restore AC power.
The mboard or Cmos battery is usually an obvious coin shaped "button" battery on the mboard - round, chrome or nickel plated, that clips into a socket. You don't need a manual to find that. You remove the AC power to the case, move a clip that holds the battery down to release it from it's socket, wait afew minutes, install the battery again with the + on the battery showing when it's installed, restore AC power.
In either case, the first time you boot the computer after that, you will get a "Cmos Checksum Error" or similar message while booting - go into the bios Setup and set at least the current date and time, save bios settings, and you won't get the "Cmos Checksum Error" or similar message while booting after that (unless the battery is dead, too weak, installed backwards, or the battery has a poor or no connection to it's socket).
Tell us the make and model of your brand name system, or if you have a generic desktop system, the make and model of the mboard.
The specific model of a brand name system is shown on a label on the outside of the case somewhere, or it can often be determined by going to the brand name's web site.
The model, sometimes the make, of a mboard in a generic desktop system is usually printed on the mboard's surface in obvious larger characters, often between the slots.
The model is often also displayed on a logo (graphical) screen early in the boot, but it's often not as specific as the specific model number.
For Dell computers, they have a Service Tag number - the specific model can be determined by using that on their site, or can often be determined there automatically by you downloading some software. The Service Tag number should be on a label on the outside of the case, probably on the bottom on a laptop, on the back on a desktop, and is often also shown in the bios Setup.
"Press Del key to enter Setup Menu"
That's common for many different mboard manufacturer's bioses, that do not have a brand name system bios version, so you probably have a generic desktop system. .
" F11 to enter Boot Menu"
That is apparently common for both some mboard manufacturer's bios versions, and some brand name system's bios versions.
"Your case has opened"
You have a desktop computer that has a switch that can indicate to the bios that the computer case has been opened, e.g. if it's a tower case, when the left side panel, as seen from the front of the computer, has been removed.
"Now i can't get to no where,...."
What do you mean when you say that?
Is the keyboard working?
If yes, what happens when you press Del or F11?
Is it a corded PS/2 or USB keyboard, or a wireless keyboard ?
Were you having a problem you were trying to fix by changing bios settings?
If so, what problem were you having?
Have you been fiddling with the connections of one or more hard or optical drives inside the computer case ?
Do you have more than one hard drive installed ?