|I used to click "Run" and then click on winword.exe/a and it would then run my documents.|
Is there a reason why you invoked Word in this manner?
I've never encountered a windword.exe file with the last letter underlined.
I’m not sure it's even a valid executable.
As for the /a option to word:
Starts Word and prevents add-ins and global templates (including the Normal template) from being loaded automatically.
The /a switch also locks the setting files; that is, the setting files cannot be read or modified if you use this switch.
The run box does have a short "memory" file, so you may have inadvertently erased the Most Recently Used file associated with the Run command.