I run PRE7 on W7-64 perfectly so your problem is likely to be something else.
Did you check your manufacturer's (rather than vendor's) web site for their latest drivers? We need to know a fair bit more abut your:
PC - hard disks, free disk space, defragged recently?, sound card, latest version of QuickTime?
FILM CLIPS - From where? how transferred to your PC? what format? what codecs (use GSpot)?
PROJECT SETTINGS - What preset have you used?
Check this out: Got a problem? Here's how best to ask for help.
Insanity is hereditary, you get it from your children
Also, some Win7 reading
Win7 Help http://social.technet.microsoft.com/Forums/en-US/category/w7itpro/
Win7 Configuration Article http://windowssecrets.com:80/comp/100218
Win7 Monitor http://windowssecrets.com:80/comp/100304
Win7 Optimizing http://www.blackviper.com/Windows_7/servicecfg.htm
Win7 Virtual XP http://www.microsoft.com/windows/virtual-pc/
Win7 Adobe Notes http://kb2.adobe.com/cps/508/cpsid_50853.html#tech
Win7 Adobe Update Server Problem http://forums.adobe.com/thread/586346?tstart=0
Win7 Photoshop http://forums.adobe.com/thread/511916?tstart=0
And, this is for Encore... but I will GUESS that the Roxio "burning module" MAY also be in Elements
BluRay problem Win7 http://forums.adobe.com/thread/400484?tstart=0
Fix Encore Win7 Problem http://forums.adobe.com/thread/528582?tstart=0 or direct to
Long File Names Cause Crashing http://forums.adobe.com/thread/588273