Spybot, i cannot find it know

When I first installed spybot S&D it ran OK, but know I cannot find the program on the xp based computer anywhere, even with search or in the dos prompt. the program is somewhat invisible. I've enabled to see all files, but no joy.
I checked the add/remove list and the program is listed and it shows the location, but theirs folder there. The resident program Spybot S&D is running in the background and is listed as icon in the right of toolbar.

I cannot also download the update from their website, I keep getting the error "Cannot copy file: Cannot read from the source file or disk " this is the same error with Process Explorer when I try and download. I've been trying for a few days now. My mate can however download these within the same same time period I try.

Have I got a spy,worm virus. I've ran ad-aware se, hijack this, norton anti-virus with internet security running, ccleaner, but still same problem.

I think what ever is creating problems here is causing other system and software problems That I have had.

Any ideas please