Here's my 2 cents worth.
IMHO, a more feature rich process utilty than Microsoft's Process Explorer is the free open source Process Hacker
It has very good reviews and my preferred process utility that has added advantages over the MS closed source utility.
Read these Vista specific instructions in this post...viewtopic.php?p=135356#p135356
...and follow the link mentioned as it also has instruction to help with correctly disabling IIS and UAC in Vista that helped the original posters with a SYSTEM issue.
The SYSTEM issue usually means that there is a Windows service occupying the ports that Apache/MySQL requires which have not been uninstalled\disabled correctly and so may be still installed - the services need to be uninstalled which will remove them from the Windows registry.
If you use the keyword system
in an advanced forum search in the XAMPP for Windows English forum
then you will see many posters had a similar issue.
Also try and use the new control panel xampp-control-3-beta.exe
found in the xampp folder.
First Stop all components and then remove any ticks in the Svc boxes then click on Exit the older control panel before double clicking on the new XCPv3.
You can then use the many new and improved features it contains including the Netstat button that will show you the ports in use.
Latest XCPv3 versions can be found here:viewtopic.php?f=16&t=48932