Suddenly unable to install application from SD card I have an HTC wildfire. I am currently developing an application which I am consistently testing on my phone. Since yesterday for some reason I am not able to install any apk of that particular app that I am building. 

The usual method of installation I use is download to SD card and then install from there. Other apps get installed with this process but not my app. 

The error message - App not installed.

I am able to download and install my app from the market. 

I have tried deleting all information from the phone regarding the app i.e cache etc but still doesnt work. 

Not sure if the phone has blocked my app ? Can it do that ..?
I did an adb install -r [apk] thanks to the comment by @eldarerathis and I got an install_failed_container_error as the reason for installation failure...

Further searching got me to this link

http://eatingbits.se/articles/2010/11/16/install_failed_container_error-when-installing-an-application-on-android/

The solution being a temp file inside .android_secure folder not getting removed. So once i deleted the file app installed properly. Thanks everyone for helping out!!