If you are unable to start Curse Client v5, and have been able to in the past, it may be due to a corrupt Microsoft ClickOnce app store. This is essentially the location on your hard drive where Windows caches per-user applications, such as Curse Client v5.
How to Fix a Corrupt Curse Client Install
From the Windows Start menu > Accessories choose Run (Or Windows Key + R)
Enter the following, depending on your version of Windows, then click the OK button:
On Windows XP: %userprofile%\Local Settings\Apps (e.g. C:\Documents & Settings\Username\Local Settings\Apps)
On Windows VISTA / 7: %userprofile%\AppData\Local\Apps (e.g. C:\users\Username\AppData\Local\Apps)
Delete the 2.0 folder
Run or Install Curse Client v5
Note: You may want to also clear out your computers Temporary files as well. You can use a program such as CCleaner to help you with the.
How to fix a corrupt ASP.NET Install
From the Windows Start menu, choose Computer
In the finder textbox, enter the following:
WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files