Ok, so I upgraded msn msnger about 2 months ago. And I want to delte the installer, because I love having a clean desktop. And every time I try, It tells me it's being used. I cant figure out what else is using it.. And the "Nirvana Box" was put on about a year ago, I delete it and it comes back randomly any suggestions?

Looks like you have an anti-virus scanner, so I'll assume it's up to date and you scanned for viruses. Did you can for malware also? Adware is good, but sometimes doesn't catch all malware. I use adware, spy bot search and distroy, and microsofts antispyware. I know it sounds like overkill on the malware part but one alone cannot detect all.

Also run a hijack this. or a process explorer to see what else is hiding in the backround. Close all extra running tasks then run highjack. You can either google the outcome yourself or post the log on some sites/boards for others to look at. Here's one.

Even fresh installs of windows can do strange things. Here is the manual way to get rid of things that just won't delete.
1. Close all open programs.
2. Open a command prompt.
3. Right-click the taskbar, and select Task Manager.
4. On the Processes tab, select Explorer.exe, and click the End Process button.
5. Minimize Task Manager, but don't close it.
6. At the command prompt, use the Delete command to remove the file/folder, and close the command prompt.
7. In Task Manager, go to File | New Task (Run).
8. In the Create New Task dialog box, enter Explorer.exe, and click OK.
9. Close Task Manager

Usually running your computer in safe mode and doing uninstalls there will prevent the malware from using the item you wish to uninstall.

Assuming that it is indeed malware and not a windows process...

Yes, hatesyou is true if it's a windows process it will reappear. I removed one believing it was malware but was always reappearing and i find out it was a windows process ... :-)

My way to delete undeletables is to open notepad, type in some nonsense and click file save, select "all file types" then save as whatever the undeletable file is called (extension included)

then you can copy this file over the undesirable undeletable, will obv ask if youd like to replace, you want yes. if it lets you do this then just delete the file.

if it wont let you replace it then...
check if your machine is running something at startup, start; run; 'msconfig' (without speech marks) and select startup. see if theres a reg key that seems to be running the file or process on startup. once identified ctrl+shift+esc will bring up the task manager, kill the process and then try to copy the file over once again.

that shud work