Cant boot in safe mode windows xp

[orangeman2010]

I recently encountered the worm.win32.netsky which totally controlled my pc. I was able to remove using various spyware programs. However, my pc then asked to update to xp SP3. when i did, and restarted, i now cannot get past the windows xp screen. I cant boot in safe mode. What can i do?
Dell inspiron laptop
windows xp media edition
no floppy disc availability:mad::mad: