I have dell inspiron, previously i have install ubuntu 11.10 on my win7 and make it dual boot. but since i want to upgrade my ubuntu version and change the partion spacing, i have delete 11.10 partion directly and extend my hardrive space(windows + ubuntu) at that moment everything is fine. then i have put 12.04 version pendrive in usb boot from usb and install the 12.04 32 bit . it was installed but can't showing dual boot option like 11.10 and my machine directly boot into win7 . so instantly i again delete my 12.04 partion .

Now i am able to login into win7 but whenever i put pendrive(12.04) into usb drive i am facing error of "grub rescue" even though i try to put lower version(11.04) it showing another error "Error: No default or UI configuration directive found boot >"

i have reinstall win7 and reformat all partion still i am facing same error :(

i need help badly.