Toshiba stuck at Windows XP screen

Hello, my Dad's Toshiba Satellite is stuck at the Windows XP screen, it won't go into Safe Mode or any other startup option. I think he tried to install Windows 7 but I'm not exactly sure. I don't have any OS discs to repair the OS, if that's needed...Oh and sometimes instead of staying on the Windows XP screen, a blue screen will come up that says "Stop: c0000221 {Bad Image Checksum} The image imagehlp.dll is possibly corrupt. The header checksum does not match the computed checksum" Hopefully you can help me fix this. Thanks in advance

UPDATE: I reinstalled the OS and now it works fine so far, thanks anyway!

No need for apologies! I appreciate your input, I was curious how to boot an OS with a flash drive