Dell Inspiron 1525 won't charge battery

Hello,

My girlfriend has a Dell Inspiron 1525 for about a year and this problem just came out a few weeks ago.
The laptop, when turned on with the charger, will not charge when plugged in: "Plugged in, not charging".

I looked over on google and found people with similar problems but I tried their solutions but the didn't work.

WHat I've noticed also is that, when I go to the BIOS, it says: AC ADAPTER UNKNOWN
Also with the Dell Diagnostics program, all the tests with the charger fails, but the battery, everything passed and seems alright.

SO, the problem is that here in Europe, Dell charges absurdly 260 Francs just to send them the Laptop for them to just have a look. I could also order a new charger and see if the problem will be solved but if it doesn't, then it would be a waste of money..

Does anyone have similar problems or tackled with something like that?
Any ideas would be also appreciated..

Thanks!