windows 7 - Unable to delete a file

I have a program that I can't uninstall. I get the following error:

There is a problem with this Windows Installer package. A program required for this install to complete could not be run. Contact your support personnel or package vendor.

The program seems to be completely romoved from Program Files except for 2 files, Which is a LaTeX log file:

QuoteTemplate.log
QuoteTemplate.synctex.gz(busy)

When I try to manually delete these files I get:

You need permission to perform this action

I click "Try Again" multiple times and it never succeeds.

When I run command prompt as administrator and try:

del C:\Program Files (x86)\dir\QuoteTemplate.log

It says Access is Denied. If I try:

cd C:\Program Files (x86)\dir

It says Access is Denied.

I thought that a corrupted program had a lock on the file, so I restarted the computer, then did all of the above again, with the same results.

Update: starting in safe mode and doing the same had the same effect.

Update: I was able to change the content of the files, I just couldn't delete them. I believe it to be because of the access permissions on dir. I was able to unlock dir using unlocker from the accepted answer. It seemed that windows explorer somehow had a lock on the file, which is why restarting didn't fix the problem. I could be wrong though.

Any ideas?

Answer

A simple tool, called unlocker can do the job easily, it disables all the 'you cannot delete ...' restrictions