Laptop stalls won't boot

Hi guys I’m trying to solve a boot-up problem on my girlfriends Gateway MX6923b laptop (XP home). When I switch it on it shows the windows screen with the light that chases from left to right but just remains on that without changing. It did at first boot into safe mode but has now stopped even doing that. I tried an XP Pro boot disc (don’t know if that matters) but get the message setup did not find any hard discs in your computer. When it did boot in safe mode I scanned it for malware & found none.
I have removed and slaved the hard disc to another computer and it works fine. I finally got to trying the Gateway Restore option but that just gets to the restore page I ask to restore but seems to do nothing from there. The time elapsed remains at 00.00. When this is running the light for the disc drive flickers a couple of times at the start and then nothing. I’m sure it’s a hardware fault it’s as thought the hard drive isn’t being found. Is there a test I can do?

Anyone any suggestions as to what I can try next?