How do I go about fixing these files and why should I have to, I didn't do anything to them except to download them. thanks in advance for your help. Hope this is the right place.
Modified just means not downloaded from the DLS or you've opened it. Safe to ignore. Obsolete means a later version is available right click and download then delete the old version.
As per John's response above. "Modified" means that you have:-
installed the asset from a source other than the DLS (e.g. a third party web site or a .cdp file), or
created the asset yourself, or
opened and modified (e.g. edited its config.txt file) an existing asset, or
cloned an existing asset
None of these is an "error" or needs fixing nor will it affect how the assets works. Content Manager is simply informing you of the current status of these assets.
"Obsolete" means that an installed asset (from what-ever source) has been superseded or obsoleted by a newer version that has also been installed. A related description, "Newer version available", means that an installed asset has a newer version available on the DLS but not yet installed.
Only if the obsoleted asset is from the DLS or another site. You cannot delete obsolete assets that are "Built-in", "Payware" or part of DLC (e.g. "Packaged").