With no drivers, which are probably non-existent for the older hardware, it won't function. If they are available, check each device in Device Manager and see if a new driver is available by visiting the device manufacturer's website. Just a note, you'll probably want more RAM than the XP machines have.
And check the link below for your hardware compatibility issues:
http://www.microsoft.com/windows/compatibility/windows-7/en-us/default.aspx
Hope this helps.
Grif
I own older an Compaq Presario SR1511NX desktop and older HP Pavilion 743g desktop. Both are currently running Windows XP. Both are Pentium 4's. HP manufactured both, but they do not provide drivers for Windows 7. Will Windows 7 work with my computers and where can I find their drivers for Windows 7?

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