well i recently downloaded backtrack because i'm interested in network penatration. i made a bootable usb dive using unetbootin and it has worked great untill i ran install.sh and tryed to install backtrack on my hdd....something happpened and grub failed so i got my windows boot disk and ran f/disk mbr and then booted windows up deleted and the linux partitions useing winodws disk manager i still have my bootable usb drive and now it wont boot....i get something like this

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ERROR:unable to locate ioapic for gsi i forget the numbers beside "gsi"
ERROR:unable to locate ioapic for gsi
ERROR:unable to locate ioapic for gsi
ERROR:unable to locate ioapic for gsi
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and then it goes to a busybox shell. at first i thought my usb drive had corrupted the files and then i tryed it in two other computers and they booted backtrack fine.
please help, i usually find the answer online but i cant find anything that helped me.