"This application failed to start because uxtheme.dll was not found. Re-installing the application may fix this problem."

Hi,

DWM.exe is Desktop Window Manager.

It is a windows process which needs to be started for the aero and other features to work on windows 7.
DWM is that gives you all those pretty effects in Windows Vista or Windows 7 Transparent windows, live taskbar thumbnails , and even the Flip3D switcher that you can disable and replace with Switcher. 
 

Method 1:

I suggest that you check whether Desktop Service Manager is running.
To do this:

a)      Click Start

b)      Type "services" in the start search box.

c)       Now check status of the "Desktop Service Manager".

d)      If it is disable set it to “Automatic’

Method 2:

You can try performing Clean Boot and check if the issue still persists to view how to perform the clean boot click on the link provided below and follow the Kb article steps.

 http://support.microsoft.com/kb/929135

Disclaimer: After you used the clean boot to resolve your problem follow Step 7 to reset the computer to start as usual.

Method 3:

I would suggest you to try performing SFC (System File Checker) scan  on your computer and check if the issue still persists. To view how to perform the SFC Scan click on the link provided and follow the Kb article steps.

How to use the System File Checker tool to troubleshoot missing or corrupted system files on Windows Vista or on Windows 7

http://support.microsoft.com/kb/929833