Ms Win Xp Pre-install Prob

[MicroStudios]

hi guyz

i have a compq laptop, its a bit old and it came with XP pro but i never installed a new windows, i only installed SP2 then uninstalled it because it was running slow and i installed SP1 and it works fine

but the problem is every time i use internet there, when i restart the machine the desktop item disappear, so i have to use System Mechanic all time to fix this problem

why is that happening?

Any suggestions?