Have you checked the 'RUN' & 'RUN ONCE' keys in the Registry?
Also check values for WMP in Registry (Software section).
Also, does a media-file start playing when WMP starts on startup?
Also i don't want to sound rude but two suggestions have been made to me even though I have mentioned it in my post that I have dont that already.
I have tried the registry there is nothing there, nothing in msconfig, i have even uninstalled software that is used not regularly and was updated when the problem started to occur.
I have just done a google and its been mentioned in other forums but no solution.
I used this forum as it was suggestions and the fact it has more active users.
you say that it's not listed in msconfig. Have you tried to run a diagnostic start up (in msconfig)? if not - try it and see if it stil opens.
Even though Media player it self is not listed there might be some other file that initiates MP.
Glad you've found the cause and hope u get it fixed now.
Just to close this thread, it's a good point you made for others to read posts carefully to avoid giving pointless advice (already done it etc). Also, it's worth remembering that an antivirus prog cannot be expected to detect trojans as well as it detects true viruses - there are specialist applications for that. You ideally need a separate application to trap viruses, trojans & spyware.
No single application I know of can do all three or even any two of the three.