Application Management not working

When logged into services.msc, I was trying to start the application management service; however, it won't restart. Error message: could not start the application management service on local computer. Error 126: the specified module could not be found. It shows the application to be in:c:\windows\system32\svchost.exe -k netsvcs. It's not there. The problem has been existing for a couple of months. It's on my laptop-Dell Vostro1500; running Windows XP HE with Service Pack 3. I've tried finding a download of the svchost.exe, thus far none are working. Tried rerunning my OS disk, but get error, system running in newest version. For whatever reason, on the laptop I am always having to go in and restart certain services\applications. Is there a solution to this end?

 

That much I knew, where can I find the download for the missing update.exe