windows 7 wont boot

hi im not sure if this is under the right category but, i have an acer aspire 4730z laptop with windows 7 ultimate the other day my battery died while i was using it and it forced shutdown and i put it on the charger and was gone all weekend i came back today to use it and it powers on and gets to the screen that says acer with the f2 boot options and then it gets to a screen with a flashing dash and then it goes black but the laptop stays fully on and the screen comes back on to the acer screen and it repeats this over and over ive tried the removing battery and power cable hold power button 30 sec and it did nothing and it wont boot into recovery at least in the ways i tried it using F8 or F8+Esc nothing seems to work i dont have a recovery disk but i do have a bootable usb with windows xp on it and when i try to boot from that it does the same as before.
I really need some help with this my Essay is due wednesday