WinDVD/PowerDVD and other apps that access the optical drive are generally slower than most other apps when you start them up. Is there a cd/dvd in your optical drive? If so, remove it and see if these apps still startup slow? Even so, 30 secs is way too long
I could be wrong, but doesn't WMP have to load the library list when it starts? Maybe that could be a cause, if your media library is very large.
Another common reason could be that the files associated with these apps are fragmented and it's taking longer to read them. Slow bootup is often because of heavy fragmentation of the startup files, and the same principle applies here...if the WMP and Win/PowerDVD files are badly fragmented, they may load slower. You may want to do a proper defrag and see if that helps.
If that doesn't help, check for nasties using a proper virus scanner. You never know...
applications are taking way too long to startup, time to check your hard drive for problems.
FWIW, on my XP 32 bit system (from which I am browsing atm) it takes about 2-3 secs to startup PowerDVD and about 1 sec to startup WMP after a cold boot. I don't have WinDVD to check its startup times.