Off the top of my head I'd guess that a BAT file should work, since it runs each process one at a time.
Right click on each thing in your Startup folder and select Properties. Each one should have some text in the "Target" field; that's the text that needs to be in your BAT file. Open up Notepad and copy those lines into a txt file one line at a time and save it as something.bat, then put that bat into your startup folder.
Might not work, but you might be lucky. If it doesn't work you might need to make a logon script, but I can't remember how those go right now.
Edit: Another thing to try would be to put a brief pause in-between each line of the bat file. You can use the sleep.exe command to do this (available
here if you don't have it). For example, a line with
SLEEP 5 would give you a 5 second pause.