i recently bought a new battery charger for my dell laptop. it worked fine for a week or 2 but now it wont charge my laptop when i plug it in.
i've found that the charger when plugged into the wall outlet isn't turning on because the little green light that is usually lit on the box of the charger isn't lit.
so after finding this out i tried using someone else's charger and it worked for a day and the next day the same problem happened. what's going on? i hope it has doesn't have something to do with my laptop itself. please help!!

First, some chargers need a load for the green light to come on.
If three chargers have died it must be your laptop that is doing it.

i dont understand whats wrong with my computer.. what do i do.. i mean, i have so much info on my computer that i cant lose. should i buy another charger? what should i do?

The fault with the laptop is unlikely to effect the data you have on your hard drive, providing you don't mess with the thing any more.
However, you are learning the hard way about backups so I would get a new charger (make sure it is exactly the right one - just because the connector fits does not mean it has the right voltage and amperage output) and before you do anything else, copy your files to a CD or flash drive or whatever you have available.
If you have the correct charger and it fails again, take the laptop to a repair shop.
You have not said where you are but if you are in UK, I can give you a name of someone who will fix it.

3 chargers tried, same trouble... The laptop's motherboard charging circuits are probably damaged. Take the laptop in for service

1. try a universal charger.
2. If you are burning chargers up, then you have one of two issues. Either your mains has incorrect voltage. (Not likely, but possible.) OR your internal voltage circuits in the laptop are bad - requires a motherboard replacement.

Buy a new battery !

Should not need to - 99% of laptops will run on mains current without a battery.

Yes they will run solely on the AC adapter. Try removing the battery while doing this. If the Laptop and the charger works normally, do what Po`Girl suggests