I'm using labview 8.5 right now and I've some projects saved using 7.1. Is there any way I can open the file with 8.5 or do I have to redo everything ?

Post your code... How can we help otherwise?

I have projects written in LabVIEW 7.1 and can open them with no problems in LabVIEW 8.5 the only problems you might encounter is driver incompatibilities and if any of your code has the block diagram removed, there might be other upgrade issues too, the release notes would contain more information. The only VIs I've found that have been too old for LabVIEW 8.5 to open at all are LabVIEW version 5.1 or older.

I cannot seem to view my Sub VIs for the port read and config. There is this question mark image on the block for the Sub VIs

As Karrisap mentions, you've got some missing vis because you have not all DAQ drivers installed. I get the same problem you do at home because I don't have any DAQ installed on that computer. It's looking for zadvd.llb that should be installed in vi.lib folder. Install your drivers and you should have no problem loading your code.

I see. Thank you very much. But how do I install the drivers ? You see I'm only in charge of the programs and the boss sends someone else to do the installation part.

You can download the latest drivers from NI website.