I am planning on making a new system of 6 computers for an office and wanted to use Ubuntu as the main OS.
Is there a program to either convert or be able to use those files so they can be used on Ubuntu?
Ubuntu use libreOffice as the default office software package.
With this software, you will be able to open/edit any file that have a Microsoft Office format, so you don't have to worry about a conversion (in must of the cases).
NOTE: You may have format issues, like don't get the exactly same design. For example I draw a simple line in PowerPoint (MO), and then when I open it with Impress (LO) I saw an arrow.
You should be able to move these files to Ubuntu, but a lot will depend on the the files and your skills. Like all projects, you should think carefully about what your future requirements will be.
Using LibreOffice to an mdb file to an odb file
You said the files were "way back on Windows XP", so presumably they are mdb files. Access used mdb as the file format through Access 2003/Office XP. LibreOffice Base is able to convert these files to odb format; but doesn't have good instructions for this in the help and requires an additional package.
b. Browse to your datasource
c. Click OK
d. On the next two screens, you can Test the connection, then save the database with a new name, and open it for editing.
LibreOffice is able to convert tables, forms, queries, and reports. It will not generally be able to convert any VBA modules.
Using Gnome mdb viewer
MDB Viewer lets you view and export the tables, schema, forms, queries, macros, and modules.
These tools are especially useful if you have an mdb file, but no longer have a licensed copy of Access.
If you were using Access 2007 on XP, you would need to first save the files in mdb format. There are currently no free tools available to convert or read accdb files.
You might also consider using Access to export the data as xml or csv files and then importing them into Base, MySql, or other freely available databases. Access and Base are good as quick methods to create front ends to data but can be limited as multi-user solutions. MySql and similar options allow you create a solution better suited for multi-users. You would then use Base to easily create a front end that can connect to MySql.
The best solution so far for accessing
If you only want to view or export the contained data you also could use an online viewer/exporter like www.mdbopener.com . mdbopener.com is using the already mentioned mdbtools for .mdb files and the jackcess library (java) for .accdb files. Disclosure: I am the creator of www.mdbopener.com