can i use vista driver  

dell hasnot provided windows 7 driver for the Vostro A860 alps touch pad, only the vista driver is available. can i try it?????? whats the worse thing that can happen in such a case

I doubt anything cataclysmic can happen. Make sure you install the driver in Vista compatibility mode. To be safe, create a system restore point before you install it, in case something happens you cant handle, you can go back to the previous good state. In any case, drivers can always be rolled back to the previous version by right clicking on them in device manager.

I responded to someone with a Toshiba laptop having this issue awhile back and the answer applies here as well. While DELL products can, and do, often require OEM drivers the Alps Touchpad is Alps specific and does not require a DELL OEM version. It would be great if DELL, and other OEM manufacturers, kept up with drivers but it does not always happen. The link provided is what I suggested and it is from HP and it worked for the gent with the Toshiba laptop and should work for you, ftp://ftp.hp.com/pub/softpaq/sp45001-45500/sp45284.exe

how do you install in vista compatibility mode

it worked for me.....