start with ,right clicking on [my]Computer go properties ,it will tell you there if you are using 32 or 64 ,it will not tell you if its capable of running 64 though ,that you will have to check with acer,com and find the specs on the laptop ,laptop getting a little old ,it may run 64 bit ,when install 64 it will not install if it doesn't find the laptop to be 64bit capable .to install 64 bit you will need win764bit dvd just found thisit appears to be capable of running 64 ,line 2 processor /speed
just wanted to add that unless you have at least 4gig of ram yours shows it will take 2x2 for 4gid ,but may only have 2x1=2gig in it now ,i don't think there is any point in installing win7 64bit ,just my opinion based on what little knowledge of the facts i have .
About my opinion 64 bit operating system is more stable then 32 bit operating system. And also 64 bit operating system has some more feature then 32 bit OS. But 64 bit operating system more hardware then 32 bit. If your system has more ram, more hard-disk space, more powerful processor then you can go for the 64 bit operating system instead of 32 bit operating system.