First let's try to start Win7. Boot the Win7 DVD, select Repair on second screen, accept any offered repair to see if it will restart.
If not, repeat and click through to Recovery Tools list to run Startup Repair repeatedly until Win7 starts. It may take up to 3 separate attempts with reboots.
If this fails, return to Recov Tools list to attempt System Restore to a point before trouble began.
If all DVD repair attempts fail, then download a burn to CD
free Partition Wizard bootable CD. Boot CD, allow files to load, select 1 for screen res, make sure Win7 is marked Active - if not Modify>Set to Active then return to Win7 DVD to run Startup Repair repeatedly.
If Win7 is marked active in Partition Wizard drive map, rightclick on it again to Browse files to see that your files are intact.
If so, post back a Camera Snap or summary of the partitioning on your HD(s) with labels and System/Active/Boot designations listed. We will help you reinstall in such a way as to access your files after install in the old Win7 from the clean reinstalled one.