Well a little more information on your problem would help mate, saying that it just doesn't work isn't really much help to rest of us trying to solve the problem.
The GeForce 6200 DOES support Aero with inbox drivers
on Vista and 7, there's no reason why it shouldn't really. Its always best to get the latest ones however so here is a direct link to the 185.85 driver
for Windows 7 x86 which is 100% compatible with that card. GeForce/ION Driver Release 185
I myself have a GeForce 6200 series card in an older desktop and it works just fine with Aero using Windows 7's inbox drivers and those ones which I have just linked you to.
Take note that Aero will be not be selected by default if you are running on 512MB of RAM (Which is not recommended). You can just simply select it through the Personalization options however.
You might also want to post your system specs as they can be helpful too.
Just another bit of help, if you are considering opting for a new graphics card then there would be no point going for a GeForce 5 series one since you already have that 6 series card. Your best bet there AGP wise would be a 7 series like the 7600GS for example.
I posted this before but I guess I'll do it again:
GeForce FX 5200 or higher support Aero in Windows Vista and Windows 7
Radeon 9550 or higher support Aero in Windows Vista and Windows 7
Hope this helps and let us know how you get on!