Desire not working properly after battery went to 0%

So i bought this phone exactly 18 days before on my B'day!
I said Nty to iPhone for this HTC Desire and i really loved it so far
(except a few things like hard to open battery cover, peanut size internal storage)

    Ok so the problem.....  

The phone was on low battery and i had to go out for a few hours...
so the phone came to 5% battery and i kept using it.. and soon it powered off. ok cool...

I charged it using the charger for few hours and its acting wierd,
I can start the phone alright, it loads up a lot of background processes etc when i start the phone,
i have Lock 2.0 installed and it shows up normally, but when i unlock it, nothing happens....
The normal Desktop pages/ whatever its called dont show!!!

I tried to call myself, and i received the call and after closing the call it stuck on the contact info. pg.

Any help?

I know.... 

So i tried to call again, and after i disconnect the call, i unlock the screen again... same thing..
Its stuck on the Call ended page.

I try to press the Find button, and it actually works.. shows the phone list...
I tried to select a contact and email... opens the Gmail... and i tried to send.. seems ok...

I guess the Android system has got corrupted or something... somethings are working fine.. but the menu button doesn't show settings or the Desktop page or anything. Just stuck on the call page now after i close email.

So is this what happens when you try to completely use up the battery 
I guess no more playing around lolz.

I don't mind Factory resetting it, All i really have on it is contacts, which i have backed up.
But i cannot goto the Settings page, except the Wifi page that opened to let me connect Gmail, and now i cannot disconnect it... But i'll manage that. (by changing Wifi pass, and rebooting it haha.)

Oh and i got some Market Apps updates when it went on wifi, but i closed it.
Maybe i'll wait for morning if it shows more updates, i will uninstall all of them.... before calling the helpline.

Thx for the help tho.

Thanks i was waiting to check with the store, if doing that will void my warranty...

so now I did a Factory reset and its working!

Thanks again~