HTC Desie eye - Other Category 15.6 GB space; Erase SD Card option disabled for backup restore

[Suma Shastry]

My phone started acting weird and slow and I started exploring and I found that the "Other" category of space is 15.6 GB

Now interesting part is

1. When I move photos to computer, the memory does not increase which is strange
2. When I went ahead for backup and reset option, erase data from SD card is completely disabled !

Any help ?