As it says at the top of this forum, we'll need much more information before we'll be able to make specific recommendations.
How fast is your processor, how much RAM do you ahve and how much free, defragmented space is on your hard drive?
What operating system are you using? Have you manually gone to Windows Update and ensured you have all of the latest updates (including the optional ones)? Have you ensured you have the latest version of Quicktime from Apple.com?
Have you gone to Premiere Elements Help menu and selected Check for Updates to ensure you have the 8.01 patch?
If the program used to launch fine, but does not now, then something has likely changed. A simple OS update, or hot-fix, can render the audio and video drivers obsolete instantly. Most programs will still work fine, but an NLE (Non Linear Editor) works more closely with those two drivers, than almost any other program on your computer.
Update both the very latest, from the mfgr's. Web site.
Next, PrE works very closely with QuickTime Player, even if you are NOT using Apple footage. QT Player needs to be updated too.
Now, a few Adobe users have had some issues with the latest ATI/AMD Catalyst drivers. Same thing happened about six mos. ago, with nVidia drivers. In those cases, the users have found that they actually had to roll-back their video drivers. With the ATI drivers, it seems that they had to go back about 2 - 3 versions, but that was a month ago, and I am sure that ATI has at least 1, and possibly 2, newer drivers out.
What happens with video drives is that extreme gaming drives the market. The video card mfgrs. focus on that segment of the market, and the video-editing crowd takes a backseat to the gamers. Sometimes, a new driver is 100% designed for the very latest games, and those programs need other things. Usually, the changes for the gamers will not affect the video editors in a negative way, but sometimes - they do. This makes it tough for people, like Steve and me, as normally, the latest driver is better. There have just been a few instances, where a user actually needed an older one. I always keep about the last 5 on my system, ready to roll-back, if necessary. So far with my nVidia drivers, I have not had to do that, but some folk have.