Yes. You will have to reset the lamp hours. It should be in your owners manual.
Copy and paste this link in your address bar if you don't have the manual:
50VS810
http://tv.manualsonline.com/manuals/mfg/hitachi/hitachi_projection_television_product_list.html
I have heard that this may work on your tv
1. Switch power ON, and press the TIMER button on the remote control
transmitter, or the RESET button on the control panel, for
approximately three seconds. The 'LAMP xxxx hr' message will appear on
the lamp timer on the bottom of the screen.
2. Press the MENU button on the remote control transmitter, or the
RESET button on the control panel, while the lamp timer is displayed.
The 'LAMP xxxx [] -> 0 [|] CANCEL' message will then appear.
3. Press the [<|] and select 0, and wait until the timer display is cleared.