Got sql error code 3417

Here is the Error log.  It seems like I messed up the folder/file access permission.  How to fix this?  thanks.
ERRORLOG

Identify what user is used to run the sqlserver service and ensure that has the appropriate permissions to the folders

TRY AddING  NETWORK SERVICE with full control permission to SQL Server install folder (C:\Program Files\Microsoft SQL Server\) and restart SQL service.

sorry please add your path m on XP

(C:\Program Files\Microsoft SQL Server\)   -- your path

This was still running fine earlier today until I added those permissions for asp.net accounts.  I removed those permission and still doesn't work.  Here is the screen shot of permission to sqluser, which I didn't modify at all.  It has read+execute permission.  Why it still doesn't work?  thank you.
sqlUser.jpg

Why did you apply permissions at the folder level for these accounts? did you mean to give them access to the database or some other purpose?

Anyway, try checking a subfolder to see if the permissions on these have been retained.
Or maybe access another PC with the same install and check permissions there.
Maybe you stopped the folder from inheriting permissions applied at a higher level?
Checke the permissions on these 2 folders
Microsoft SQL Server\MSSQL.1

What account does the MSSQL service run under? Check that account has read/write access to the folder where you made changes

This sql express has been running just fine for a couple of weeks now.  The only thing I change today was adding those 2 account (aspnet and IUSR_*) to the folder permission.  Yes, all sub folder and files inherited the permission.  After that, the sql doesn't work so I remove those 2 account permissions and reboot but still doesn't work.  I did not change anything else so I hesitate to change anything suggested here because the old settings worked.  I didn't have to give these folder permission to any accounts after I install the sql server.  I only did that today trying to fix my Sitecore, cms, problem.
In the last attached file, I assume the highlighted user, sqlserver2005xxxxxxx, is the user used to run the sqlserver service.  Isn't it?  If not, then how do I identify which userid is it using to run the sql server?
I'm running sql 2005 express on Windows 7 Enterprise PC.  

I gave the sqlserver2005xxxxxxx account full control and now I can start the sql instance but one of database is now empty.  I lost all the tables, ...  that were under this database.  What is going on and what happened here?  How can i find out or how to fix this?  Thank you.

right that's good we are back online, that service would need to write to the folder.

Which database has lost the tables? A system database or a user created one?

Do you have management studio so that you can see the server?
If so, does the DB (with missing tables) show as suspect or restoring or just look normal?

Do you have a backup of this DB that you could use to do a restore?

It's a user database.  It looks like other database except it doesn't have the small + sign to expand it because there is nothing under it.  I cannot look at its property, detach or delete it.  I have this database file on my hard drive where it was but how do I get it back to the sql server?  Thanks.   I'm still very frustrated with file/folder permission messing up my sql server.

Jacko72 was first to respond but QPR has more specific instruction on how to proceed and QPR was also answering questions along the way.  Thank you.