slow peformance

Hi all,

i have assembled my pc from local store it's not a dell model

even after upgrading from 256 mb to 1gb memory card hardly find any difference in the performance.

i have recently relaoded xp sp2 and and other general softwares like office, pdf, mobile suite,etc.

I have two question for whom i am looking an answer : -

1) what are the ideal causes of system performing very slow ?

2) when i start my system a window opens with name window host login sciprt and my document windows open without pressing any key i have checked in start up nothing is there so how do i diable in msconfig so that my document doesn't open whenever i start my pc ?

3) I have run windows utility disk fragmentation, disk clean up what else i should do to improve the performance ?

Thanks in advance.