Putting windows 7 SSD from one computer into another.

[allergen]

I have a SSD with windows 7 (that I added and installed the OS) in my HP M9500Y. Recently the M9500Y has been having issues with the motherboard overheating and I have decided to turn to my previous computer. I took the SSD out and put it in my HP M7674N, which is a windows XP media center computer. When i went to boot from the SSD it would go to "starting windows" and right before the flag comes up reset. Then it would say windows failed to start and run the system repair which turned up nothing (only said to unplug any CDs or new hardware). It boots fine from the original hard drive with XP but not the SSD i put in from the other computer. I have tried unplugging the HDD so that only the SSD was connected, but it turned the same result. I have also tried putting in the windows 7 disk and selecting repair windows but it found nothing. I am wondering if there is just an easy way to get this SSD booting in the M7674N without having to reinstall the OS.
The specs for the computer are:
m9500y:
http://h20566.www2.hp.com/portal/site/hpsc/template.PAGE/public/kb/docDisplay/?sp4ts.oid=3824167&spf_p.tpst=kbDocDisplay&spf_p.prp_kbDocDisplay=wsrp-navigationalState%3DdocId%253Demr_na-c01616194-20%257CdocLocale%253D%257CcalledBy%253D&javax.portlet.begCacheTok=com.vignette.cachetoken&javax.portlet.endCacheTok=com.vignette.cachetoken

M7674N:
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00787409&tmp_task=prodinfoCategory&cc=us&dlc=en&lc=en&product=3271566

*I put the video card from the m9500y into the M7674N. The video card is different from the one in the link because it was replaced under warranty.

Thanks for your help.

 

[Vexillarius]

Did you make sure SATA Mode is set to the same setting as in your M9500Y?

 

[allergen]

Did you make sure SATA Mode is set to the same setting as in your M9500Y?

I just tried every option now but it still won't boot.