time of installaion of other software

i have win200 professional

a p4 sys with 256 mb of ram

when ever i install any software its taking lot of time to first start the installation wizard and after that there is no sign of operation for some time and then after some time the process automatically shows up on the screen

i have tried to update my version of win200
and also updated the bios of my p4 board

can u suggest me some ideas