To install 2.1 in car

Hello,
i would like to install my creative 2.1 on my car whether it will make any problem to my car system

it should work with the rca outputs of the radio.. otherwise you need a 'line to preamp' convertor.
then you need a 12 volt to 120 volt power invertor (less complicated than tearing apart the creative 2.1 to learn if the power supply takes the 120 volts and steps it down to 12 volts)

i must say though.. i tried to put my klipsch promedia 2.1 subwoofer in the trunk for some bass and the amplifier wasnt powerful enough.
it sounded okay with the subwoofer on the front seat though.

50 watts just wasnt enough for the subwoofer to play loud enough.

besides, my power invertor uses a 'modified sine-wave' which isnt a pure sinewave.
i plugged the amplifier into an extension cord ran from the house and it sounded only a little bit better.

doesnt seam like it was worth my time.

are you hoping to use the main speakers or the subwoofer?
because using the main speakers to make the audio louder might be worth it.

i think it would be easier to purchase a seriously cheap amp and subwoofer combo kit for about $150 new.
doesnt mean there will be lots of detail in the audio.. but it will provide something when there is nothing.

in all honesty.. if you get a radio with adjustable time alignment, you can make the speakers sound better.
but it will make the midrange and treble less loud.

for the price of a power invertor.. it might be cheaper for you to get a really cheap amp and speaker combo kit.

sometimes you can run the amplifier in 'tri-mode'
this means you hookup one speaker to the left channel
one speaker to the right channel
and then bridge the subwoofer.
if you look hard, you might find the speaker and amp combo for $50 and a cheap (maybe used) subwoofer for $50.

i'm not trying to stop you from doing what you want to do.
i just want to inform you that the results might not be worth your time and effort.
and if you have to purchase a power invertor, it might be better to spend the same amount of money on a speaker and amp combo.