No need to apologize for having basic knowledge! We all started that way, and that is why we have these Forums.
The Firefox Profile is located here:
C:\Documents and Settings\user_name\Application Data\Mozilla\Firefox\Profiles NOTE:
These files are hidden by default. To see hidden files
1. On the Tools menu in Windows Explorer, click Folder Options
2. Click the View tab
3. Under Hidden files and folders, click Show hidden files and folders
4. Disable "Hide File Extensions for Known Files."
5. Click OK.
Once you find the Profiles folder, then right click and select: Copy
Then create a folder on your C:\ drive, and name it Backup
Now right click the Backup folder and select: Paste
All your Profile data is now saved.
Next: Click on Start | Settings | Control Panel | Add/Remove
Select Firefox from the Program List and remove the program
Now delete the Firefox Program folder located here:
C:\Program Files\Mozilla Firefox
Delete the Firefox folder located here:
C:\Documents and Settings\user_name\Application Data\Mozilla\Firefox
Run your Registry Cleaner, and remove all instances of Firefox REBOOT YOUR PC
Download another Firefox install file from here: Firefox 126.96.36.199
Install Firefox, and create a new Profile
Once you have created the Profile, open Firefox, and set up your Preferences
Close Firefox, and open Windows Explorer
Open the C:\Backup\Profiles\Firefox\xxxxxxxx.yourprofilename
Copy these files to the NEW Firefox xxxxxxxx.yourprofilename
signons.txt or it may be named signons2.txt
When you copy the above files, you will be prompted as to whether you want to overwrite the existing files. When prompted, answer YES.
That should get you back up and running. There is no doubt something in your current Profile that is corrupt, and that is keeping Firefox from starting.
Post back with your results.