Hello Ngaers, and welcome to Seven Forums.
If these are shortcuts that do this, then try the lnk
download in the tutorial below.
If these are EXE files, then try the exe download in the tutorial below.
These will restore these file extensions default associations to hopefully fix this for you if this is the issue. Default File Type Associations - Restore
If the above does not help, then you might see if doing a system restore
using a restore point dated before this happened may be able to fix it for you.
Hope this helps,