Try this
Open CMD as Admin and type these commands
1. DISKPART
2. LIST DISK
3. SELECT DISK 1 (replace the number with disk number of your PD)
4. CLEAN
5. CREATE PARTITION PRIMARY
6. SELECT PARTITION 1
7. ACTIVE
8. FORMAT FS=NTFS (This can take a while)
9. ASSIGN LETTER=U (OR ANY WHICH IS FREE AND YOU LIKE)
Than Mount 7 or Vista ISO as K Drive and than type this command as Admin
K:\BOOT\BOOTSECT.EXE /NT60 U:After this Copy/Extract all content from .ISO to your PenDrive
That's It
(Please Post Result)Uvais