HTC is working really hard to address the screen responsive issue on the Touch HD. The fix isn’t a full ROM update, so you smartphone won’t have to be wiped. Rather, it’s an executable that runs on your PC and copies over an installable CAB via ActiveSync, which can be downloaded from the HTC Site.

According to HTC, the problem is described as such:

Sometimes the screen stops responding for about 3 to 5 seconds when running an application that needs to use the stylus to click the screen repeatedly within a short time. For example, the windows built-in software like SMS, email, solitaire, etc.

Source: MoDaCo