iPhone 3g porblem plz help

[mcp2009]

whenever i plug my iphone in the charger it freezes and acts VERY slow and when it doesnt decide to freeze it charges for five minutes and then says the battery is full. it froze for a while in the beginning and then stopped and then the charger would always say full after 5 mins so i just charged in comp (thats the only way) and now its freezing and acting slow

[glj100]

I would put the iphone to DFU mode and restore the firmware.