I had Premiere Pro CS4 on an XP machine with 3GB of RAM and an Intel 2.13 GHz processor and things worked OK. Then I migrated to Win 7, added a Gig stick so I have 4GB and now Premiere is very hard to use. Can't preview video -- audio plays -- and I can't scrub. Serious lag to the point I can't edit. I went to Adobe help, I've set virtual memory per instructions, scratch disks are with the originals...what do I do? How do I allocate mor RAM so I can at least use Premiere?
If you mean by 'migrating' that you have not made a fresh install, deactivate your copy of Adobe and do a clean install of everything. Else give more details.